Post Effective Amendment to Registration Statement by Investment Company Form 485APOS

As filed with the U.S. Securities and Exchange Commission on August 21, 2024

Securities Act File No. 333-191151

Investment Company Act File No. 811-22887

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-1A

REGISTRATION STATEMENT

	UNDER THE SECURITIES ACT OF 1933	☐
	Pre-Effective Amendment No.	☐
	Post-Effective Amendment No. 38	☒
	and/or
	REGISTRATION STATEMENT
	UNDER THE INVESTMENT COMPANY ACT OF 1940	☐
	Amendment No. 40	☒
	(Check appropriate box or boxes)
	Calamos ETF Trust
	(Exact Name of Registrant as Specified in Charter)
	2020 Calamos Court
	Naperville, Illinois
	(Address of Principal Executive Offices)
	60563
	(Zip Code)
	Registrant's Telephone Number, including Area Code: (630) 245-7200
	Erik D. Ojala
	2020 Calamos Court
	Naperville, Illinois 60563
	(Name and Address of Agent for Service)
	With Copies to:
	Paulita A. Pike and Rita Rubin
	Ropes & Gray LLP
	191 North Wacker Drive, 32nd Floor
	Chicago, Illinois 60606
	Approximate Date of Proposed Public Offering: As soon as practicable following the effectiveness of the Registration Statement.

It is proposed that this filing will become effective:
☐immediately upon filing pursuant to paragraph (b)
☐on [ ] pursuant to paragraph (b)
☐60 days after filing pursuant to paragraph (a)(1)
☒on August 30, 2024 pursuant to paragraph (a)
☐75 days after filing pursuant to paragraph (a)(2)
☐ on pursuant to paragraph (a)(2) of Rule 485.

If appropriate, check the following box:

☐ This post-effective amendment designates a new effective date for a previously filed post-effective amendment.

This Post-Effective Amendment to the Registrant's Registration Statement on Form N-1A relates only to Calamos Laddered S&P 500 Structured Alt Protection ETF (the "Fund") and supersedes the prior Post-Effective Amendment No. 37 filed under the Securities Act of 1933 and Post Effective Amendment No. 39 filed under the Investment Company Act of 1940 of the Trust's Registration Statement filed under Form N-1A on July 12, 2024 relating to the Fund, and does not otherwise delete, amend, or supersede any information relating to any other series of the Registrant.

CALAMOS ETF TRUST

CONTENTS OF POST EFFECTIVE AMENDMENT

This Registration Statement consists of the following papers and documents:

Cover Sheet

Part A - Prospectus - Calamos Laddered S&P 500 Structured Alt Protection ETF

Part B - Statement of Additional Information

Part C - Other Information

Signature Page

Exhibit Index

The information in this Prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This Prospectus is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any state where the offer of sale is not permitted.

Subject to Completion
August 21, 2024

Fund Name		Ticker		Exchange
Calamos Laddered S&P 500® Structured Alt Protection ETFTM		[To Come]		Cboe BZX Exchange, Inc.

Prospectus September [TO COME], 2024

The fund listed above (the "Fund") is a series of the Calamos ETF Trust (the "Trust") and an exchange-traded fund ("ETF"). The Fund lists and principally trades its shares on the Cboe BZX Exchange, Inc. (the "Exchange").

The U.S. Securities and Exchange Commission ("SEC") has not approved or disapproved these securities or passed upon the accuracy or adequacy of this prospectus. Any representation to the contrary is a criminal offense.

Table of Contents

Calamos Laddered S&P 500® Structured Alt Protection ETFTM		1
Other Important Information Regarding Fund Shares		14
Additional Information About Investment Strategies and Related Risks		15
Fund Facts		28
Who Manages the Fund?		28
How to Buy and Sell Shares		29
Dividends, Other Distributions and Taxes		31
Net Asset Value		34
Fund Service Providers		35
Premium/Discount Information		36
Investments by Other Investment Companies		36
Financial Highlights		37
Other Information		38

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Calamos Laddered S&P 500^® Structured Alt Protection ETF^TM

Investment Objective

Calamos Laddered S&P 500 Structured Alt Protection ETF (the "Fund") seeks to provide investors with capital appreciation.

Fees and Expenses of the Fund

The following table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund ("Fund Shares"). Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.

Annual Fund Operating Expenses (ongoing expenses that you pay each year as a percentage of the value of your investments):

Management Fees			0.10	%
Distribution and/or Service Fees (12b-1)			0.00	%
Other Expenses1			0.00	%
Acquired Fund Fees and Expenses2			0.69	%
Total Annual Fund Operating Expenses3			0.79	%

1 "Other Expenses" is an estimate based on the expenses the Fund expects to incur for the current fiscal year.

2 "Acquired Fund Fees and Expenses" include certain expenses incurred in connection with the Fund's investment in various exchange-traded funds ("ETFs"). The amount shown is based on estimated amounts for the current fiscal year.

3 The "Total Annual Fund Operating Expenses" in this fee table may not correlate to the expense ratios in the Fund's financial highlights and financial statements because the financial highlights and financial statements reflect only the operating expenses of the Fund and do not include Acquired Fund Fees and Expenses, which are fees and expenses incurred indirectly by the Fund through its investments in certain underlying investment companies.

Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated, and then sell all of your Fund Shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs, whether you sell or hold your Fund Shares, would be:

Year 1		Year 3
$	81		$	252

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund Shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the example, affect the Fund's performance. Because the Fund has not yet commenced operations, portfolio turnover information is unavailable at this time.

Principal Investment Strategies

The Fund seeks to achieve its investment objective by providing investors with US large-cap equity market exposure while attempting to limit downside risk through a laddered portfolio of twelve Calamos S&P 500^® Structured Alt Protection ETFs (the "Underlying ETFs"). The term "laddered portfolio" refers to the Fund's investment in multiple Underlying ETFs that have target outcome period expiration dates which occur on a rolling, or periodic, basis. See below for a discussion of "target outcome periods" and their meaning within the strategies of the Underlying ETFs. The rolling or "laddered" nature of the investments in the Underlying ETFs creates diversification of investment time period compared to the risk of acquiring or disposing of any one Underlying ETF at any one time. This diversification of investment time period is intended to mitigate the risk of failing to benefit from the downside protection of a single Underlying ETF due to the timing of investment in such Underlying ETF and the relative price of the reference asset or having limited or no upside potential remaining because of the cap of a single Underlying ETF. The Fund's laddered approach is intended to allow the Fund to continue to benefit from increases in the value of the SPDR^® S&P 500^® ETF Trust ("SPY"), while limiting downside losses. Depending on when the Fund acquires shares of an Underlying ETF, even with a laddered approach, the cap and/or downside protection of an Underlying ETF may be exhausted unless the Fund acquires shares at the beginning of a Target Outcome Period (as defined below). The Fund does not typically buy shares at the beginning of the Target Outcome Period. Unlike the Underlying ETFs, the Fund itself does not pursue a target outcome strategy. The protection is only provided by the Underlying ETFs and the Fund itself does not provide any stated downside protection against losses. The Fund will likely not receive the full benefit of the Underlying ETF downside protections and could have limited upside potential. The Fund's returns are limited by the caps of the Underlying ETFs.

In order to understand the Fund's strategy and risks, it is important to understand the strategies and risks of the Underlying ETFs. See "Additional Information on the Fund's Investment Objective and Strategies" for a discussion of the principal investment strategies of the Underlying ETFs.

Under normal market conditions, the Fund will invest substantially all of its assets in the Underlying ETFs, which seek to provide investors with returns (before fees and expenses) that match the price return of SPY, up to a predetermined upside cap, while providing downside protection (before fees and expenses) against SPY losses, over a defined one-year outcome period. The Fund intends only to acquire shares of Underlying ETFs in the secondary market and will not engage in any principal transactions with the Underlying ETFs. The Fund and each Underlying ETF are advised by Calamos Advisors LLC ("Calamos" or the "Adviser"). PDR Services, LLC ("PDR") serves as SPY's sponsor. The investment objective of SPY is to seek to provide investment results that, before expenses, correspond generally to the price and yield performance of the S&P 500^® Index. See "SPDR^® S&P 500^® ETF Trust" below for more information.

The Underlying ETFs invest substantially all of their assets in FLexible EXchange^® Options ("FLEX Options") on SPY. FLEX Options are customizable exchange-traded option contracts guaranteed for settlement by the Options Clearing Corporation. Each Underlying ETF uses FLEX Options to employ a "target outcome strategy." Target outcome strategies seek to produce pre-determined investment outcomes based upon the performance of an underlying security or index (in this case, SPY). The pre-determined outcomes sought by the Underlying ETFs, which include downside protection against (before fees and expenses) SPY losses and a cap on upside potential, are based on the price return of SPY over an approximate one-year period beginning on the first business day in the month for which each Underlying ETF is named and ending on the last business day of the preceding month in the following year (the "Target Outcome Period"). Each Underlying ETF establishes a new cap annually at the beginning of each Target Outcome Period. See "Capital Protection and Cap" below under "Additional Information About Investment Strategies and Related Risks."

Each Underlying ETF's strategy has been specifically designed to produce the outcomes (before fees and expenses) based upon SPY's returns over the duration of a Target Outcome Period. At the end of each Target Outcome Period, an Underlying ETF's FLEX Options are generally allowed to expire or be sold at or near their expiration, and the proceeds are used to purchase (or roll into) a new set of FLEX Options expiring in approximately one year. This means that approximately every 30 days, one of the Underlying ETFs will undergo a "reset" of its cap and a refresh of its downside protection. At any given time after the initial ramp up period, the Fund will generally hold one Underlying ETF with FLEX Options expiring within one month, a second Underlying ETF with FLEX Options expiring within two months, a third Underlying ETF with FLEX Options expiring within three months, etc., up to and including twelve months. The rolling or "laddered" nature of the investments in the Underlying ETFs creates diversification of investment time period and market level (meaning the price of SPY at any given time) compared to the risk of acquiring or disposing of any one Underlying ETF at any one time. Because the Fund typically will not acquire shares of the Underlying ETFs on the first day of a Target Outcome Period and may dispose of shares of the Underlying ETFs before the end of the Target Outcome Period, the Fund may experience investment returns that are very different from those that the Underlying ETFs seek to provide. If an Underlying ETF has experienced certain levels of either gains or losses since the beginning of its current Target Outcome Period, there may be little to no ability for the Fund to achieve gains or benefit from the downside protection for the remainder of the Target Outcome Period.

When an investor purchases shares of a single Underlying ETF, his or her potential outcomes are limited by the Underlying ETF's stated cap and downside protection over a defined time period (depending on when the shares were purchased). Alternatively, the Fund's laddered approach provides a diversified exposure to all of the Underlying ETFs in a single investment. By owning a laddered portfolio of Underlying ETFs, the Fund has the ability to continue to benefit from increases in the value of SPY and to provide a level of downside protection as one of the Underlying ETFs will reset its cap and refresh its downside protection every month based on the price of SPY at the time of the reset. In other words, the continual and periodic "refreshing" of the Underlying ETF caps and downside protection at current SPY prices is intended to allow the Fund to continue to benefit from increases in the value of SPY, while limiting downside losses. This approach reduces the risk inherent in the Underlying ETFs of having the upside potential for an entire Target Outcome Period capped out in cases of rapid appreciation of SPY. It also reduces the risk of failing to benefit from an individual Underlying ETF downside protection in cases where SPY has depreciated. Approximately every 30 days, one of the Underlying ETFs will undergo a reset of its cap and a refresh of its downside protection, meaning that investors will have the ability to benefit from any appreciation in SPY for future periods up to the respective caps of the Underlying ETFs and will have the benefit of the downside protection for future periods. A laddered portfolio can diversify timing risk, similar to how laddered bond portfolios seek to manage timing risks for fixed-income investors.

The Fund intends only to acquire shares of Underlying ETFs in the secondary market and will not engage in any principal transactions with the Underlying ETFs. The Fund intends to generally rebalance its portfolio to equal weight (i.e., 8.33% per Underlying ETF) semi-annually. During the Ramp-Up Period the Fund will rebalance monthly to add newly-launched Underlying ETFs. The Fund also will acquire and dispose of Underlying ETFs in connection with the creation and redemption of Creation Units between semi-annual rebalances. In between such rebalances, market movements in the prices of the Underlying ETFs may result in the Fund having temporary larger exposures to certain Underlying ETFs compared to others. Under such circumstances, the Fund's returns would be more greatly influenced by the returns of the Underlying ETFs with the larger exposures. If an over-weighted Underlying ETF underperforms the other Underlying ETFs, the Fund will experience returns that are inferior to those that would have been achieved if the Underlying ETFs were equally weighted. See Significant Exposure Risk below.

The current list of Underlying ETFs in the Fund's portfolio can be found at https://www.calamos.com/capabilities/structured-protection-etfs/. The Fund's website will provide, on a daily basis, the proportion of the Fund's assets invested in each Underlying ETF at any given time. Each Underlying ETF's website provides important information (including Target Outcome Period start and end dates and the cap (both gross and net of fees) and downside protection both at the start of the Underlying ETF's Target Outcome Period and on any particular day relative to the end of the Target Outcome Period).

Although this website information may be useful in understanding the investment strategies of the Underlying ETFs, it is limited in providing an investor of the Fund with all of the risks and potential outcomes associated with an investment in the Underlying ETFs. For example, it does not provide a direct example of your potential investment return in the Fund because of the Fund's laddered exposure to the Underlying ETFs in which each one of the Underlying ETFs will reset its cap and refresh its downside protection annually based on prevailing market conditions.

The Fund is classified as "non-diversified" under the Investment Company Act of 1940, as amended (the "1940 Act"). The Fund's investment strategy may include active and frequent trading. The Fund may not invest 25% or more of the value of its total assets in securities of issuers in any one industry or group of industries except to the extent that the underlying referenced index of the Underlying ETFs invests more than 25% of its assets in an industry or group of industries. This restriction does not apply to obligations issued or guaranteed by the U.S. government, its agencies or instrumentalities, or securities of other investment companies. As of August 15, 2024, SPY had significant investments in information technology companies.

Ramp-Up Period

At the current time, four of the Underlying ETFs are available for investing. For the following months - the Fund will rebalance until June 2025 when the Fund is expected to have equal weights of 8.33% of each Underlying Fund. During the Ramp-Up Period the Fund will be over weighted in certain Underlying Funds which could cause the Fund to experience returns that are inferior to those that would have been achieved if the Underlying ETFs were equally weighted. During this time, the Fund's ability to take advantage of the "laddered" nature of the investments in the Underlying ETFs will be limited.

PROSPECTUS |

Calamos Laddered S&P 500^® Structured Alt Protection ETF^TM

Principal Risks

An investment in the Fund is subject to risks, and you could lose money on your investment in the Fund. There can be no assurance that the Fund will achieve its investment objective. You should not consider investing in the Fund if your investment objective differs from the Fund's investment objective or if you are not willing to accept the principal risks associated with an investment in the Fund. The risks associated with an investment in the Fund can increase during times of significant market volatility. Your investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The principal risks are presented in alphabetical order to facilitate finding particular risks and comparing them with other funds. Each risk summarized below is considered a "principal risk" of investing in the Fund, regardless of the order in which it appears. The principal risks of investing in the Fund include:

ABSENCE OF AN ACTIVE MARKET RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market makers or authorized participants. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares and market makers are under no obligation to make a market in the Fund's shares. Additionally, only a limited number of institutions act as authorized participants for the Fund and only an authorized participant may engage in creation or redemption transactions directly with the Fund and are not obligated to submit purchase or redemption orders for Creation Units. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund's portfolio securities and the Fund's market price. Any trading halt or other problem relating to the trading activity of these market makers or any issues disrupting the authorized participants' ability to proceed with creation and/or redemption orders could result in a dramatic change in the spread between the Fund's net asset value and the price at which the Fund's shares are trading on the Exchange, which could result in a decrease in value of the Fund's shares. This reduced effectiveness could result in Fund shares trading at a premium or discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund, and none of those Authorized Participants is obligated to engage in creation and/or redemption transactions. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem, Fund Shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Authorized Participant concentration risk may be heightened for ETFs, such as the Fund, that invest in securities issued by non-U.S. issuers or other securities or instruments that have lower trading volumes.

CAP CHANGE RISK. A new Underlying ETF cap is established at the beginning of each Target Outcome Period and is dependent on prevailing market conditions. As a result, a cap may rise or fall from one Target Outcome Period to the next and is unlikely to remain the same for consecutive Target Outcome Periods.

CAPPED UPSIDE RISK. Each Underlying ETF's strategy seeks to provide returns (before fees and expenses) that match the price return of SPY for shares acquired on the first day of a Target Outcome Period and held for the entire Target Outcome Period, subject to a pre-determined upside cap. Because the Fund will acquire shares of the Underlying ETFs in connection with creations of new shares of the Fund and during each semi-annual rebalance and Ramp-Up Period, the Fund typically will not acquire Underlying ETF shares on the first day of a Target Outcome Period. Likewise, the Fund will dispose of shares of the Underlying ETFs in connection with redemptions of shares of the Fund and during each semi-annual rebalance, and such disposals typically will not occur on the last day of a Target Outcome Period. In the event that the Fund acquires Underlying ETF shares after the first day of a Target Outcome Period and the Underlying ETF has risen in value to a level near or at the cap (because the Fund's potential gain will be limited to the difference between the Underlying ETF's NAV on the date the Fund purchases Underlying ETF shares and the cap), there may be little or no ability for the Fund to experience an investment gain on its shares, however, the Fund will remain vulnerable to downside risks. This could be true for all of the Underlying ETFs held by the Fund at a certain point in time severely limiting the Fund's ability to participate in gains during that time. If SPY experiences gains during a Target Outcome Period, an Underlying ETF will not participate in those gains beyond the cap. If the Fund buys Underlying ETF shares when the price exceeds the cap, the Fund will not experience any gain regardless of the performance of SPY.

CASH HOLDINGS RISK. To the extent the Fund holds cash positions, the Fund risks achieving lower returns and potential lost opportunities to participate in market appreciation which could negatively impact the Fund's performance and ability to achieve its investment objective.

COSTS OF BUYING AND SELLING FUND SHARES. Due to the costs of buying or selling Fund Shares, including brokerage commissions imposed by brokers and bid/ask spreads, frequent trading of Fund Shares may significantly reduce investment results and an investment in Fund Shares may not be advisable for investors who anticipate regularly making small investments.

COUNTERPARTY RISK. Underlying ETF transactions involving a counterparty are subject to the risk that the counterparty will not fulfill its obligation to the Underlying ETF. Counterparty risk may arise because of the counterparty's financial condition (i.e., financial difficulties, bankruptcy, or insolvency), market activities and developments, or other reasons, whether foreseen or not. A counterparty's inability to fulfill its obligation may result in significant financial loss to an Underlying ETF and, in turn, the Fund. An Underlying ETF may be unable to recover its investment from the counterparty or may obtain a limited recovery, and/or recovery may be delayed. The OCC acts as guarantor and central counterparty with respect to the FLEX Options. As a result, the ability of an Underlying ETF to meet its objective depends on the OCC being able to meet its obligations. In the unlikely event that the OCC becomes insolvent or is otherwise unable to meet its settlement obligations, an Underlying ETF and, in turn, the Fund could suffer significant losses.

DERIVATIVES RISK. Derivatives are instruments, such as options, futures and forward foreign currency contracts, whose value is derived from that of other assets, rates or indices. The use of derivatives for non-hedging purposes may be considered more speculative than other types of investments. Derivatives can be used for hedging (attempting to reduce risk by offsetting one investment position with another) or non-hedging purposes. Hedging with derivatives may increase expenses, and there is no guarantee that a hedging strategy will work. While hedging can reduce or eliminate losses, it can also reduce or eliminate gains. In addition, derivative instruments are subject to counterparty risk, meaning that the party with whom the Fund enters into a derivative transaction may experience a significant credit event and/or may be unwilling or unable to make timely settlement payments or otherwise honor its obligations. Changes in the value of a derivative may not correlate perfectly with the underlying asset, rate or index, and the Fund could lose more than the principal amount invested.

PROSPECTUS

EQUITY SECURITIES RISK. The securities markets are volatile, and the market prices of the SPY's securities may decline generally. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions. If the market prices of the securities owned by the SPY fall, the value of your investment in the Fund will decline.

FLEX OPTIONS RISK. The Underlying ETFs invest in FLEX Options. Trading FLEX Options involves risks different from, or possibly greater than, the risks associated with investing directly in securities. The Underlying ETFs may experience substantial downside from specific FLEX Option positions and certain FLEX Option positions may expire worthless. The FLEX Options are listed on an exchange; however, no one can guarantee that a liquid secondary trading market will exist for the FLEX Options. In the event that trading in the FLEX Options is limited or absent, the value of the Underlying ETFs' FLEX Options may decrease. In a less liquid market for the FLEX Options, liquidating the FLEX Options may require the payment of a premium (for written FLEX Options) or acceptance of a discounted price (for purchased FLEX Options) and may take longer to complete. A less liquid trading market may adversely impact the value of the FLEX Options and Underlying ETFs' shares and result in the Underlying ETFs and, in turn, the Fund being unable to achieve their investment objective. Less liquidity in the trading of the Underlying ETF's FLEX Options could have an impact on the prices paid or received by the Underlying ETFs for the FLEX Options in connection with creations and redemptions of the Underlying ETF's shares. Depending on the nature of this impact to pricing, an Underlying ETF may be forced to pay more for redemptions (or receive less for creations) than the price at which it currently values the FLEX Options. Such overpayment or under collection may impact the value of the Underlying ETF and whether the Underlying ETF can satisfy its investment objective. Additionally, in a less liquid market for the FLEX Options, the liquidation of a large number of options may more significantly impact the price. A less liquid trading market may adversely impact the value of the FLEX Options and the value of the Underlying ETFs. The trading in FLEX Options may be less deep and liquid than the market for certain other exchange-traded options, non-customized options or other securities.

FLEX OPTIONS VALUATION RISK. The FLEX Options held by the Underlying ETFs will be exercisable at the strike price only on their expiration date. Prior to the expiration date, the value of the FLEX Options will be determined based upon market quotations or using other recognized pricing methods. The FLEX Options are also subject to correlation risk, meaning the value of the FLEX Options does not increase or decrease at the same rate as SPY (although they generally move in the same direction) or its underlying securities. The value of the FLEX Options prior to the expiration date may vary because of factors other than the value of SPY, such as interest rate changes, changing supply and demand, decreased liquidity of the FLEX Options, a change in the actual and perceived volatility of the stock market and SPY and the remaining time to expiration. FLEX Option prices may also be highly volatile and may fluctuate substantially during a short period of time. During periods of reduced market liquidity or in the absence of readily available market quotations for the holdings of the Underlying ETFs, the ability of the Underlying ETFs to value the FLEX Options becomes more difficult and the judgment of the Underlying ETFs' investment adviser (employing the fair value procedures approved by the Board of Trustees of the Trust) may play a greater role in the valuation of the Underlying ETFs' holdings due to reduced availability of reliable objective pricing data. Consequently, while such determinations may be made in good faith, it may nevertheless be more difficult for the Underlying ETFs to accurately assign a daily value. Under those circumstances, the value of the FLEX Options will require more reliance on the investment adviser's judgment than that required for securities for which there is an active trading market. This creates a risk of mispricing or improper valuation of the FLEX Options which could impact the value paid for shares of the Underlying ETFs.

FUND-OF-FUNDS RISK. Shareholders of the Fund will experience investment returns that are different than the investment returns provided by an Underlying ETF. The Fund does not itself pursue a defined outcome strategy, nor does the Fund itself provide downside protection against SPY losses. Because the Fund will typically not purchase an Underlying ETF on the first day of a Target Outcome Period, it is not likely that the stated outcome of the Underlying ETF will be realized by the Fund. The Fund will be continuously exposed to the investment profiles of each of the Underlying ETFs during their respective Target Outcome Periods. The Fund, with its aggregate exposure to each of the Underlying ETFs, may have investment returns that are inferior to that of any single Underlying ETF or group of Underlying ETFs over any given time period. In between the semi-annual rebalance period of the Index, because the Fund is not equally weighted on a continuous basis, the Fund may be exposed to one or more Underlying ETFs disproportionately when compared to other Underlying ETFs. In such circumstances, the Fund will be subject to the over-weighted performance of such Underlying ETF. As a shareholder in other ETFs, the Fund bears its proportionate share of each ETF's expenses, subjecting Fund shareholders to duplicative expenses.

INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund's shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund's net asset value could be negatively impacted and the Fund's market price may be below the Fund's net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

INFORMATION TECHNOLOGY COMPANIES RISK. SPY invests significantly in information technology companies. Information technology companies produce and provide hardware, software and information technology systems and services. These companies may be adversely affected by rapidly changing technologies, short product life cycles, fierce competition, aggressive pricing and reduced profit margins, the loss of patent, copyright and trademark protections, cyclical market patterns, evolving industry standards and frequent new product introductions. In addition, information technology companies are particularly vulnerable to federal, state and local government regulation, and competition and consolidation, both domestically and internationally, including competition from foreign competitors with lower production costs. Information technology companies also heavily rely on intellectual property rights and may be adversely affected by the loss or impairment of those rights.

LARGE CAPITALIZATION COMPANIES RISK. SPY invests in the securities of large capitalization companies. Large capitalization companies may grow at a slower rate and be less able to adapt to changing market conditions than smaller capitalization companies. Thus, the return on investment in securities of large capitalization companies may be less than the return on investment in securities of small and/or mid capitalization companies. The performance of large capitalization companies also tends to trail the overall market during different market cycles.

MANAGEMENT RISK. The Fund is subject to management risk because it is an actively managed portfolio. In managing the Fund's investment portfolio, the portfolio managers will apply investment techniques and risk analyses that may not produce the desired result. There can be no guarantee that the Fund will meet its investment objective.

MARKET FLUCTUATION TAX RISK. The Fund is acquiring shares of the Underlying ETFs in the open market. When the Fund sells shares of the Underlying ETFs in the open market, the Fund will recognize gain or loss on the disposition of the shares, which could have a negative impact on Fund returns. In addition, note that the Fund may, under certain circumstances, effect a portion of its creations and redemptions for cash rather than in-kind. If the Fund effects redemptions for cash, it may be required to sell shares of the Underlying ETFs in order to obtain the cash needed to distribute redemption proceeds. Any recognized gain on these sales by the Fund will generally cause the Fund to recognize a gain it might not otherwise have recognized, or to recognize such gain sooner than would otherwise be required if it were to distribute such shares only in-kind. The Fund intends to distribute these gains to shareholders to avoid being taxed on this gain at the fund level and otherwise comply with the special tax rules that apply to it. This strategy may cause shareholders to be subject to tax on gains they would not otherwise be subject to, or at an earlier date than if they had made an investment in a different ETF. Moreover, cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. These brokerage fees and taxes, which will be higher than if the Fund sold and redeemed its shares entirely in-kind, will be passed on to those purchasing and redeeming Creation Units in the form of creation and redemption transaction fees. In addition, these factors may result in wider spreads between the bid and the offered prices of the Fund's shares than for ETFs that distribute portfolio securities in-kind. The Fund's use of cash for creations and redemptions could also result in dilution to the Fund and increased transaction costs, which could negatively impact the Fund's ability to achieve its investment objective.

MARKET RISK. The risk that the securities markets will increase or decrease in value is considered market risk and applies to any security. If there is a general decline in the stock or fixed-income market, it is possible your investment may lose value regardless of the individual results of the companies in which the Fund invests.

NEW FUND RISK. The Fund is a recently organized investment company with a limited operating history. As a result, prospective investors have a limited track record or history on which to base their investment decision.

NON-DIVERSIFICATION RISK. The Fund is classified as "non-diversified" under the 1940 Act. As a result, the Fund is only limited as to the percentage of its assets which may be invested in the securities of any one issuer by the diversification requirements imposed by the Internal Revenue Code of 1986, as amended (the "Code"). The Fund may invest a relatively high percentage of its assets in a limited number of issuers. As a result, the Fund may be more susceptible to a single adverse economic or regulatory occurrence affecting one or more of these issuers, experience increased volatility and be highly invested in certain issuers.

OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund's service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund's ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

OPTIONS RISK. The use of options by the Underlying ETFs involves investment strategies and risks different from those associated with ordinary portfolio securities transactions and depends on the ability of the Underlying ETFs' portfolio managers to forecast market movements correctly. The prices of options are volatile and are influenced by, among other things, actual and anticipated changes in the value of the underlying instrument, or in interest or currency exchange rates, including the anticipated volatility, which in turn are affected by fiscal and monetary policies and by national and international political and economic events. The effective use of options by the Underlying ETFs also depends on the Underlying ETFs' ability to terminate option positions at times deemed desirable to do so. There is no assurance that the Underlying ETFs will be able to effect closing transactions at any particular time or at an acceptable price. In addition, there may at times be an imperfect correlation between the movement in values of options and their underlying securities and there may at times not be a liquid secondary market for certain options.

PREMIUM/DISCOUNT RISK. The market price of the Fund's shares will generally fluctuate in accordance with changes in the Fund's net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund's investment advisor cannot predict whether shares will trade below at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund's investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund's shares may become less liquid in response to deteriorating liquidity in the market for the Fund's underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund's shares and their net asset value and the bid/ask spread on the Fund's shares may widen.

SECTOR RISK. To the extent the SPY invests a significant portion of its assets in a particular sector, a greater portion of the Underlying ETF's and Fund's performance may be affected by the general business and economic conditions affecting that sector. Each sector may share economic risk with the broader market, however there may be economic risks specific to each sector. As a result, returns from those sectors may trail returns from the overall stock market, and it is possible that the SPY may underperform the broader market.

SIGNIFICANT EXPOSURE RISK. The Fund intends to generally rebalance its portfolio to equal weight (i.e., 8.33% per Underlying ETF) semi-annually, in connection with the reset of each Underlying ETF. In between such rebalances, market movements in the prices of the Underlying ETFs may result in the Fund having temporary larger exposures to certain Underlying ETFs compared to others. Under such circumstances, the Fund's returns would be more greatly influenced by the returns of the Underlying ETFs with the larger exposures.

SPY EQUITY RISK. Because each Underlying ETF holds FLEX Options that reference SPY, each Underlying ETF has exposure to the equity securities markets. Equity securities prices fluctuate for several reasons, including changes in investors' perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

SPY RISK. Each Underlying ETF invests in FLEX Options that reference SPY, which subjects the Underlying ETFs to certain of the risks of owning shares of an ETF as well as the types of instruments in which SPY invests. The value of SPY will fluctuate over time based on fluctuations in the values of the securities held by SPY, which may be affected by changes in general economic conditions, expectations for future growth and profits, interest rates and the supply and demand for those securities. In addition, ETFs are subject to absence of an active market risk, premium/discount risk and trading issues risk. Brokerage, tax and other expenses may negatively impact the performance of the Underlying ETF and, in turn, the value of the Fund's shares. An ETF that tracks an index may not exactly match the performance of the index due to cash drag, differences between the portfolio of the ETF and the components of the index, expenses and other factors.

TARGET OUTCOME PERIOD RISK. Each Underlying ETF's investment strategy is designed to deliver returns that match the price return of SPY if shares are bought on the day on which the Underlying ETF enters into the FLEX Options (i.e., the first day of a Target Outcome Period) and held until those FLEX Options expire at the end of the Target Outcome Period subject to the cap. Because the Fund will acquire shares of the Underlying ETFs in connection with creations of new shares of the Fund and during each quarterly rebalance, the Fund typically will not acquire Underlying ETF shares on the first day of a Target Outcome Period. Likewise, the Fund will dispose of shares of the Underlying ETFs in connection with redemptions of shares of the Fund and during each quarterly rebalance, and such disposals typically will not occur on the last day of a Target Outcome Period. In the event the Fund acquires shares after the first day of a Target Outcome Period or disposes of shares prior to the expiration of the Target Outcome Period, the value of the Fund's investment in Underlying ETF shares may not be protected against a decline in the value of SPY and may not participate in a gain in the value of SPY for the Fund's investment period.

TAX RISK FROM INVESTMENT IN OTHER INVESTMENT COMPANIES. The Fund has based its analysis of its qualification as a "regulated investment company" ("RIC") as defined by the Code on the belief that its portfolio funds are themselves RICs. If a portfolio fund were to lose its status as a RIC for purposes of the Code, the Fund may fail its requirement to have a diversified portfolio, and, thus, lose its own RIC status. If the Fund did not qualify as a RIC for any taxable year and certain relief provisions were not available, the Fund's taxable income would be subject to tax at the Fund level and to a further tax at the shareholder level when such income is distributed. In such event, in order to requalify for taxation as a RIC, the Fund might be required to recognize unrealized gains, pay substantial taxes and interest and make certain distributions. This would cause investors to incur higher tax liabilities than they otherwise would have incurred and would have a negative impact on Fund returns. In such event, the Fund's Board of Trustees may determine to reorganize or close the Fund or materially change the Fund's investment objective and strategies. In the event that the Fund fails to qualify as a RIC, the Fund will promptly notify shareholders of the implications of that failure.

TRADING ISSUES RISK. Trading in Fund Shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in Fund Shares inadvisable. In addition, trading in Fund Shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange's "circuit breaker" rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund's assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

UNDERLYING ETF CONCENTRATION RISK. An Underlying ETF may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Underlying ETF's investments more than the market as a whole, to the extent that the Underlying ETF's investments are concentrated in the securities and/or other assets of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector, market segment or asset class.

UNDERLYING ETF EXPOSURE RISK. An investment in the Fund may provide returns that are lower than the returns that an investor could achieve by investing in one or more of the Underlying ETFs alone. Additionally, if one or more of the Underlying ETFs has exceeded its cap at the time that you invest in the Fund, you may derive no benefit from the Fund's investment in that Underlying ETF until the next reset of the Underlying ETF. Likewise, if one or more of the Underlying ETFs has decreased in value below its downside protection at the time that you invest in the Fund, you may derive no downside protection from the Fund's investment in that Underlying ETF. See Capital Protection Risk and Capped Upside Risk above. As a shareholder in other ETFs, the Fund bears its proportionate share of each ETF's expenses, subjecting Fund shareholders to duplicative expenses. The Fund does not itself pursue a target outcome strategy and does not provide any downside protection against Underlying ETF losses.

UNDERLYING ETF RISK. The Fund's investment in shares of the Underlying ETFs subjects it to the risks of owning the securities held by the Underlying the ETF, as well as the same structural risks faced by an investor purchasing shares of the Fund, including absence of an active market risk, premium/discount risk and trading issues risk. As a shareholder in another ETF, the Fund bears its proportionate share of the ETF's expenses, subjecting Fund shareholders to duplicative expenses.

Fund Performance

The Fund had not commenced operations as of the date of this prospectus. Once available, the Fund's performance information, and information that gives some indication of the risks of an investment in the Fund by comparing the Fund's performance with a broad measure of market performance, will be available on the Fund's website at: www.calamos.com. Past performance (before and after taxes) is not an indication of future performance.

Investment Adviser

Calamos Advisors LLC ("Calamos Advisors" or the "Adviser")

Portfolio Managers

PORTFOLIO MANAGER/ FUND TITLE (IF APPLICABLE)		PORTFOLIO MANAGER EXPERIENCE IN THE FUND		PRIMARY TITLE WITH ADVISER
David O'Donohue		Since September 2024		SVP, Sr. Co-Portfolio Manager
Jimmy Young		Since September 2024		SVP, Co-Portfolio Manager
Eli Pars		Since September 2024		SVP, Sr. Co-Portfolio Manager
Jason Hill		Since September 2024		SVP, Sr. Co-Portfolio Manager
Anthony Vecchiolla		Since September 2024		VP, Co-Portfolio Manager

PROSPECTUS |

Other Important Information Regarding Fund Shares

Portfolio Holdings. The Fund's portfolio holdings are disclosed on its website daily after the close of trading on the Exchange and prior to the opening of trading on the Exchange the following day. A description of the Fund's policies and procedures with respect to the disclosure of such Fund's portfolio holdings is available in the Fund's Statement of Additional Information ("SAI").

Premium/Discount Information. Information about the premiums and discounts at which the Fund's Shares have traded will be available at www.calamos.com.

Purchase and Sale of Fund Shares

The Fund will issue (or redeem) Fund Shares to certain institutional investors (typically market makers or other broker-dealers) only in large blocks of Fund Shares known as "Creation Units." Creation Unit transactions are conducted in exchange for the deposit or delivery of a designated portfolio of in-kind securities and/or cash.

Individual Fund Shares may only be purchased and sold on the Exchange, other national securities exchanges, electronic crossing networks and other alternative trading systems through your broker-dealer at market prices. Because Fund Shares trade at market prices rather than at net asset value ("NAV"), Fund Shares may trade at a price greater than NAV (premium) or less than NAV (discount). When buying or selling Fund Shares in the secondary market, you may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase Fund Shares (bid) and the lowest price a seller is willing to accept for Fund Shares (ask) (the "bid-ask spread"). Recent information regarding the Fund's NAV, market price, premiums and discounts, and bid-ask spreads is available at https://www.calamos.com/.

Tax Information

Net investment income and capital gains distributions you receive from the Fund generally are subject to federal income taxes and may also be subject to state and local taxes. The Fund intends to distribute net investment income and capital gains, if any, at least annually.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer or other financial intermediary (such as a bank), such Fund and its related companies may pay the intermediary for the sale of Fund Shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary's website for more information.

CALAMOS LADDERED S&P 500^® STRUCTURED ALT PROTECTION ETF^TM

Additional Information About Investment Strategies and Related Risks

The Fund is a series of Calamos ETF Trust and is regulated as an "investment company" under the 1940 Act. The Fund is actively managed and does not seek to track the performance of an index. The Fund's investment objective to seek to provide investors with capital appreciation is non-fundamental and may be changed by the Board of Trustees of the Trust (the "Board") without shareholder approval. Unless an investment policy is identified as being fundamental, all investment policies included in this prospectus and the Fund's Statement of Additional Information ("SAI") are non-fundamental and may be changed by the Board without shareholder approval. If there is a material change to the Fund's principal investment strategies, you should consider whether the Fund remains an appropriate investment for you. There is no guarantee that the Fund will achieve its investment objective.

The Fund is classified as "non-diversified" under the 1940 Act, as amended. The Fund's investment strategy may include active and frequent trading. The Fund may not invest 25% or more of the value of its total assets in securities of issuers in any one industry or group of industries except to the extent that the underlying referenced index of the Underlying ETFs invests more than 25% of its assets in an industry or group of industries. This restriction does not apply to obligations issued or guaranteed by the U.S. government, its agencies or instrumentalities, or securities of other investment companies.

Under normal market conditions, the Fund will invest at least 80% of its net assets (plus any borrowings for investment purposes) in ETFs. Shareholders will be provided with 60-day written notice of any change to this policy.

The Fund may invest in ETFs in excess of the limits imposed under the 1940 Act on investments in other investment companies. Accordingly, the Fund intends to rely on Section 12(d)(1)(G) of the 1940 Act in connection with such investments.

By investing substantially all of its assets in the Underlying ETFs, the Fund seeks to provide upside participation (before fees and expenses) in the price return of SPY, while attempting to limit downside risk (due to the downside protection provided for in each of the Underlying ETFs). Each Underlying ETF's strategy has been specifically designed to produce the outcomes based upon SPY's price returns over the duration of a Target Outcome Period. At the end of each Target Outcome Period, an Underlying ETF's FLEX Options are generally allowed to expire or sold at or near their expiration, and the proceeds are used to purchase (or roll into) a new set of FLEX Options expiring in approximately one year. This means that approximately every 30 days, one of the Underlying ETFs will undergo a "reset" of its cap and a refresh of its downside protection. At any given time, once fully implemented, the Fund will generally hold one Underlying ETF with FLEX Options expiring within one month, a second Underlying ETF with FLEX Options expiring within two months, a third Underlying ETF with FLEX Options expiring within three months, etc., up to and including twelve months. The rolling or "laddered" nature of the Underlying ETFs creates diversification of investment time period and market level compared to the risk of acquiring or disposing of any one Underlying ETF at any one time.

When an investor purchases shares of a single Underlying ETF, his or her potential outcomes are limited by the Underlying ETF's stated cap and downside protection over a defined time period (depending on when the shares were purchased). Alternatively, the Fund's laddered approach provides a diversified exposure to all of the Underlying ETFs in a single investment. By owning a laddered portfolio of Underlying ETFs, the Fund has the ability to continue to benefit from increases in the value of SPY and to provide a level of downside protection as one of the Underlying ETFs will reset its cap and refresh its downside protection every month based on the price of SPY at the time of the reset. In other words, the continual and periodic "refreshing" of the Underlying ETF caps and downside protections at current SPY prices is intended to allow the Fund to continue to benefit from increases in the value of SPY, while limiting downside losses. This approach reduces the risk inherent in the Underlying ETFs of having the upside potential for an entire Target Outcome Period capped out in cases of rapid appreciation of SPY. It also reduces the risk of failing to benefit from an individual Underlying ETF's downside protection in cases where SPY has depreciated. Approximately every 30 days, one of the Underlying ETFs will undergo a reset of its cap and a refresh of its downside protection, meaning that investors will have the ability to benefit from any appreciation in SPY for future periods up to the respective caps of the Underlying ETFs and will have the benefit of the downside protection for future periods. A laddered portfolio can diversify the timing risk, similar to how laddered bond portfolios seek to manage timing risks for fixed-income investors. Unlike the Underlying ETFs, the Fund itself does not pursue a target outcome strategy. The downside protection is only provided by the Underlying ETFs and the Fund itself does not provide any stated downside protection against losses. The Fund will likely not receive the full benefit of the Underlying ETF downside protection and could have limited upside potential. The Fund's returns are limited by the caps of the Underlying ETFs.

The target outcomes each Underlying ETF seeks for investors that hold its shares for an entire Target Outcome Period are as follows, though there can be no guarantee these results will be achieved:

●

If SPY appreciates over the Target Outcome Period, the combination of FLEX Options held by the Underlying ETF seeks to provide upside participation (before the Underlying ETF's fees and expenses) matching that of the price return of SPY, up to a cap that is determined at the start of the Target Outcome Period.

●	If SPY decreases over the Target Outcome Period, the combination of FLEX Options held by the Underlying ETF seeks to provide downside protection of the of SPY losses, prior to taking into account the Underlying ETF's fees and expenses.

Because the Fund will acquire shares of the Underlying ETFs in connection with creations of new shares of the Fund and during each semi-annual rebalance, the Fund typically will not acquire Underlying ETF shares on the first day of a Target Outcome Period and therefore is likely to experience investment returns very different from those that the Underlying ETF seeks to provide. Likewise, the Fund will dispose of shares of the Underlying ETFs in connection with redemptions of shares of the Fund and during each semi-annual rebalance, and such disposals typically will not occur on the last day of a Target Outcome Period, and therefore the Fund is likely to experience investment returns very different from those that the Underlying ETFs seek to provide. The Fund will likely not receive the full benefit of the Underlying ETF downside protection and could have limited upside potential. When the Fund acquires and disposes of shares of the Underlying ETFs in between semi-annual rebalances in connection with the creation and redemption of creation units, it will acquire such shares pro-rata based on the then current weightings of the Underlying ETFs in the Fund's portfolio.

Ramp-Up Period

At the current time, four of the Underlying ETFs are available for investing. For the following months - the Fund will rebalance until June 2025 when the Fund is expected to have equal weights of 8.33% of each Underlying Fund. During the Ramp-Up Period the Fund will be over weighted in certain Underlying Funds which could cause the Fund to experience returns that are inferior to those that would have been achieved if the Underlying ETFs were equally weighted. During this time, the Fund's ability to take advantage of the "laddered" nature of the investments in the Underlying ETFs will be limited.

The Underlying ETFs

On the first day of each new Target Outcome Period, an Underlying ETF resets by investing in a new set of FLEX Options that are designed to provide a new cap for the new Target Outcome Period. This means that each Underlying ETF's cap will change for each Target Outcome Period based upon prevailing market conditions at the beginning of each Target Outcome Period. Each Underlying ETF will be perpetually offered and not terminate after the initial or any subsequent Target Outcome Period. Approximately one week prior to the end of the current Target Outcome Period, the Underlying ETF's website will be updated to alert existing shareholders that the Target Outcome Period is approaching its conclusion and will disclose the anticipated cap range for the next Target Outcome Period.

While the cap and downside protection of an Underlying ETF provide the intended outcomes only for investors that hold their shares throughout the complete term of the Target Outcome Period, an investor, like the Fund, can expect their shares to generally move in the same direction as SPY during a Target Outcome Period. However, during a Target Outcome Period, an investor's shares may not experience price movement to the same extent as the price movement of SPY. During a Target Outcome Period there may be periods of significant disparity between an Underlying ETF's NAV and the price performance of SPY. As SPY's price and the Underlying ETF's NAV change over a Target Outcome Period, an investor, like the Fund, acquiring shares after the start of a Target Outcome Period will likely have a different return potential than an investor who purchased shares at the start of the Target Outcome Period. This is because while the cap and downside protection for a Target Outcome Period are fixed levels that are calculated in relation to the SPY price and the Underlying ETF's NAV at the start of a Target Outcome Period and that remain constant throughout the Target Outcome Period, an investor, like the Fund, purchasing shares at market value during a Target Outcome Period likely purchased shares at a price that is different from the Underlying ETF's NAV at the start of the Target Outcome Period (i.e., the NAV that the cap and downside protection reference). For example, if the Fund acquires shares of an Underlying ETF during a Target Outcome Period at a time when the Underlying ETF has decreased in value from its value on the first day of the Target Outcome Period, the Fund's downside protection will essentially be decreased by the amount of the decrease in the Underlying ETF's value. Conversely, if the Fund acquires shares of an Underlying ETF during a Target Outcome Period at a time when the Underlying ETF has increased in value from its value on the first day of the Target Outcome Period, the cap for that portion of the Fund's portfolio will essentially be decreased by the amount of the increase in the Underlying ETF's value. See "Capital Protection and Cap" below for additional information. In addition, the current price of SPY is likely to be different from the price of SPY at the start of a Target Outcome Period, meaning the Fund may not experience the intended return of an Underlying ETF.

Capital Protection and Cap

Each Underlying ETF seeks to provide capital protection to absorb 100% of losses (before fees and expenses) of the SPY at the end of each Outcome Period. Each Underlying ETF's capital protection level will be reduced by the Underlying ETF's management fees and further reduced by any brokerage commissions, trading fees, taxes and extraordinary expenses not included in the Underlying ETF's management fee. If the Underlying ETF is required to increase its holdings of cash during the Outcome Period to pay fees and expenses incurred by it, the capital protection level may be further reduced. The Underlying ETFs do not seek to provide capital protection against 100% of losses (before fees and expenses) of such Underlying ETF as of any time other than the end of the Outcome Period.

Depending on the Underlying ETF's NAV at the time of purchase, the Fund may lose its entire investment in an Underlying ETF. An investment in the Fund is only appropriate for shareholders willing to bear those losses. Despite the intended downside protection of the Underlying ETFs, the Fund could lose its entire investment.

The returns of each Underlying ETF are subject to a cap for each Target Outcome Period. Unlike other investment products, the potential returns the Fund can receive from an Underlying ETF are subject to a pre-determined upside return cap that represents the maximum percentage return the Fund can achieve from an investment in the Underlying ETF for an entire Target Outcome Period. In the event SPY experiences gains over a Target Outcome Period, the Underlying ETF seeks to provide investment returns before fees and expenses that match the percentage increase of SPY, but any percentage gains over amount of the cap will not be experienced by the Underlying ETF or, in turn, the Fund. This means that if SPY experiences gains for a Target Outcome Period in excess of the cap for that Target Outcome Period, neither the Underlying ETF nor the Fund will benefit from those excess gains. Additionally, if a Target Outcome Period has begun and an Underlying ETF has increased in value to a level near to the cap, an investor, like the Fund, purchasing at that price has little or no ability to achieve gains but remains vulnerable to downside risks. Therefore, regardless of the performance of SPY, the cap is the maximum return the Fund can achieve from an investment in the Underlying ETF for that Target Outcome Period.

Each Underlying ETF's cap is set on the first day of each Target Outcome Period. The defined cap applicable to a Target Outcome Period will vary based on prevailing market conditions at the time, including then-current interest rate levels, SPY volatility, and the relationship of puts and calls on the underlying FLEX Options.

The cap level is a result of the design of each Underlying ETF's principal investment strategy. In order to provide the downside protection, the Underlying ETF purchases a series of put and call FLEX Options on the first day of a Target Outcome Period. As the purchaser of these FLEX Options, the Underlying ETF is obligated to pay a premium to the seller of those FLEX Options. The portfolio managers calculate the amount of premiums that the Underlying ETF will owe on the put options acquired and sold to provide the downside protection and will then go into the market and sell call options with terms that entitle the Underlying ETF to receive premiums such that the net amount of premiums paid per unit of SPY is approximately equal to the price per unit of shares of SPY. The cap is the strike price of those sold FLEX Options.

The following line graph and bar chart illustrate the hypothetical returns that the FLEX Options seek to provide for each Underlying ETF with respect to the price performance of SPY in certain illustrative scenarios over the course of a Target Outcome Period. The caps in the line graph and bar chart below are for illustration only and the actual caps may be different. The line graph and bar chart do not take into account payment by the Underlying ETFs of fees and expenses. There is no guarantee that an Underlying ETF will be successful in providing these investment outcomes for any Target Outcome Period.

• The line graph above represents the Underlying ETF's hypothetical intended return profile based upon the performance of SPY.

• The cap in the line graph above is for illustration only and the actual caps may be different.

Explanation of diagram:

1. Calamos S&P 500 Structured Alt Protection ETF - Participation Layer: The dotted grey line represents the first layer, which involves purchasing a near zero-strike (i.e., deep in-the-money) call on the reference asset, at a pre-determined strike to provide full participation to the price return of the underlying reference asset. In other words, the full price participation provided by this layer provides potential gains and losses that are tantamount to that of owning the underlying reference asset outright, except that this layer does not participate in the dividend yield of the underlying reference asset.

2. Capital Protection Layer: The solid grey line represents the second layer, which involves purchasing an at-the-money put option, which produces protection equal to 100% of losses (before fees and expenses) of the price return of the reference asset, over the Outcome Period.

3. Upside Participation Layer (the "Cap"): The solid black line illustrates the final layer, which involves selling an out-of-the-money call, thereby creating the upside cap. The strike price at which the call is sold is determined so that the combined net options purchase price is approximately equal to the underlying asset's current value. The cost of this layer is a credit equal to the price that would make the total package "no-cost" or fully financed.

Investors, like the Fund, purchasing shares of an Underlying ETF during a Target Outcome Period will experience different results.

General Information about FLEX Options

FLEX Options are customizable exchange-traded option contracts guaranteed for settlement by the Options Clearing Corporation ("OCC"). The OCC guarantees performance by each of the counterparties to the FLEX Options, becoming the "buyer for every seller and the seller for every buyer," with the goal of protecting clearing members and options traders from counterparty risk. The OCC may make adjustments to FLEX Options for certain significant events, as more fully described in the Fund's Statement of Additional Information. Although guaranteed for settlement by the OCC, FLEX Options are still subject to counterparty risk with the OCC and subject to the risk that the OCC may fail to perform the settlement of the FLEX Options due to bankruptcy or other adverse reasons. The FLEX Options that the Underlying ETFs will hold that reference SPY will give the Underlying ETFs the right or the obligation to either receive or deliver shares of SPY, or the right or the obligation to either receive or deliver a cash payment on the option expiration date based upon the difference between the SPY's value and a strike price, depending on whether the option is a put or call option and whether the Underlying ETF purchases or sells the option. The FLEX Options held by the Underlying ETFs are European style options, which are exercisable at the strike price only on the FLEX Option expiration date. The Underlying ETFs will generally, under normal conditions, hold FLEX Options for each Outcome Period. The Underlying ETFs will purchase call options (giving the Underlying ETFs the right to receive shares of SPY or a cash payment) and put options (giving the Underlying ETF the right to deliver shares of SPY or a cash payment), while simultaneously selling (i.e., writing) call options (giving the Underlying ETF the obligation to deliver shares of SPY or a cash payment). The Underlying ETFs intend to structure the FLEX Options so that any amount owed by the Underlying ETF on the written FLEX Options will be covered by payouts at expiration from the purchased FLEX Options. As a result, the Underlying Funds expect the FLEX Options to be fully covered and no additional collateral will be necessary during the duration of the then current Outcome Period. The Underlying ETF receives premiums in exchange for the written FLEX Options and pays premiums in exchange for the purchased FLEX Options. The OCC and securities exchanges on which the FLEX Options are listed do not charge ongoing fees to writers or purchasers of the FLEX Options during their life for continuing to hold the option contracts but may charge transaction fees. Each of the FLEX Options purchased and sold throughout the Underlying ETFs' respective Outcome Periods will have the same terms, such as strike price and expiration date, as the FLEX Options purchased and sold on the first day of the Outcome Period. On the FLEX Options expiration date, the Underlying ETFs intend to sell the FLEX Options prior to their expiration or cash-settle the FLEX Options and use the resulting proceeds to purchase new FLEX Options for the next Outcome Period.

SPDR^® S&P 500^® ETF Trust ("SPY")

SPY is an exchange-traded unit investment trust that uses a replication strategy, meaning it invests in as many of the stocks in the S&P 500 Index as is practicable. PDR Services, LLC ("PDR") serves as SPY's sponsor. The investment objective of SPY is to seek to provide investment results that, before fees and expenses, correspond generally to the price and yield performance of the S&P 500 Index (the "Index"). See below for a description of SPY's principal investment strategies and risks. You can find SPY's prospectus and other information about the ETF, including the statement of additional information and most recent reports to shareholders, online at https://us.spdrs.com/en/etf/spdr-sp-500-etf-SPY. The summary information below regarding SPY comes from its filings with the SEC. You are urged to refer to the SEC filings made by SPY and to other publicly available information (e.g., SPY's annual reports) to obtain an understanding of SPY's business and financial prospects.

The following description of SPY's principal investment strategies was taken directly from SPY's prospectus, dated January 26, 2024 (defined terms have been modified).

"SPY seeks to achieve its investment objective by holding a portfolio of the common stocks that are included in the Index (the "Portfolio"), with the weight of each stock in SPY's Portfolio substantially corresponding to the weight of such stock in the Index. In SPY's prospectus, the term "Portfolio Securities" refers to the common stocks that are actually held by SPY and make up SPY's Portfolio, while the term "Index Securities" refers to the common stocks that are included in the Index, as determined by the index provider, S&P Dow Jones Indices LLC ("S&P"). At any time, SPY's Portfolio will consist of as many of the Index Securities as is practicable. To maintain the correspondence between the composition and weightings of Portfolio Securities and Index Securities, State Street Global Advisors Trust Company (the "Trustee") or its parent company, State Street Bank and Trust Company ("SSBT") adjusts SPY's Portfolio from time to time to conform to periodic changes made by S&P to the identity and/or relative weightings of Index Securities in the Index. SPY's Trustee or SSBT aggregates certain of these adjustments and makes changes to SPY's Portfolio at least monthly, or more frequently in the case of significant changes to the Index. SPY may pay transaction costs, such as brokerage commissions, when it buys and sells securities (or "turns over" its Portfolio). Such transaction costs may be higher if there are significant rebalancings of Index Securities in the Index, which may also result in higher taxes when SPY's units are held in a taxable account. These costs, which are not reflected in SPY's estimated annual Trust ordinary operating expenses, affect SPY's performance. During the most recent fiscal year, SPY's portfolio turnover rate was 2% of the average value of its portfolio. SPY's portfolio turnover rate does not include securities received or delivered from processing creations or redemptions of SPY's units. Portfolio turnover will be a function of changes to the Index as well as requirements of SPY's trust agreement. ... Although SPY may fail to own certain Index Securities at any particular time, SPY generally will be substantially invested in Index Securities, which should result in a close correspondence between the performance of the Index and the performance of SPY. ... SPY does not hold or trade futures or swaps and is not a commodity pool... . The Index includes five hundred (500) selected companies, all of which are listed on national stock exchanges and spans a broad range of major industries. ... Since 1968, the Index has been a component of the U.S. Commerce Department's list of Leading Indicators that track key sectors of the U.S. economy. Current information regarding the market value of the Index is available from market information services. The Index is determined, comprised and calculated without regard to SPY."

As of August 15, 2024, SPY had significant investments in information technology companies.

Non-Principal Investments

Cash Equivalents and Short-Term Investments

The Fund may invest in securities with maturities of less than one year or cash equivalents, or it may hold cash. The percentage of the Fund invested in such holdings varies and depends on several factors, including market conditions. For temporary defensive purposes and during periods of high cash inflows or outflows, the Fund may invest part or all of its assets in these securities or it may hold cash. During such periods, the Fund may not be able to achieve its investment objective. The Fund may adopt a defensive strategy when the portfolio managers believe securities in which such Fund normally invests have elevated risks due to political or economic factors and in other extraordinary circumstances. For more information on eligible short-term investments, see the SAI.

Illiquid Investments

The Fund may invest up to 15% of its net assets in securities and other instruments that are, at the time of investment, illiquid (determined using the Securities and Exchange Commission's standard applicable to investment companies, i.e., any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment). For this purpose, illiquid investments may include, but are not limited to, certain restricted securities (securities the disposition of which is restricted under the federal securities laws), certain securities that may only be resold pursuant to Rule 144A under the Securities Act, and certain repurchase agreements, among others.

Temporary Investments

In response to market, economic, political, or other conditions, the Fund may temporarily invest for defensive purposes that are inconsistent with the Fund's principal investment strategies. If the Fund does so, different factors could affect the Fund's performance, and the Fund may not achieve its investment objective.

Risks of Investing in the Fund

This prospectus describes the risks you may face as an investor in the Fund. It is important to keep in mind that generally, investments with a higher potential reward also have a higher risk of losing money. The reverse is also commonly true: the lower the risk, the lower the potential reward. However, as you consider an investment in the Fund, you should also take into account your tolerance for the daily fluctuations of the financial markets and whether you can afford to leave your money in this investment for a long period of time to ride out down periods.

As with any security, there are market and investment risks associated with your investment in the Fund. The value of your investment will fluctuate over time, and it is possible to lose money. Each risk summarized below is considered a "principal risk" of investing in the Fund, regardless of the order in which it appears.

Principal Risks

ABSENCE OF AN ACTIVE MARKET RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market makers or authorized participants. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares and market makers are under no obligation to make a market in the Fund's shares. Additionally, only a limited number of institutions act as authorized participants for the Fund and only an authorized participant may engage in creation or redemption transactions directly with the Fund and are not obligated to submit purchase or redemption orders for Creation Units. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund's portfolio securities and the Fund's market price. Any trading halt or other problem relating to the trading activity of these market makers or any issues disrupting the authorized participants' ability to proceed with creation and/or redemption orders could result in a dramatic change in the spread between the Fund's net asset value and the price at which the Fund's shares are trading on the Exchange, which could result in a decrease in value of the Fund's shares. This reduced effectiveness could result in Fund shares trading at a premium or discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund, and none of those Authorized Participants is obligated to engage in creation and/or redemption transactions. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem, Fund Shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Authorized Participant concentration risk may be heightened for ETFs, such as the Fund, that invest in securities issued by non-U.S. issuers or other securities or instruments that have lower trading volumes.

CAP CHANGE RISK. A new Underlying ETF cap is established at the beginning of each Target Outcome Period and is dependent on prevailing market conditions. As a result, a cap may rise or fall from one Target Outcome Period to the next and is unlikely to remain the same for consecutive Target Outcome Periods.

CAPPED UPSIDE RISK. Each Underlying ETF's strategy seeks to provide returns (before fees and expenses) that match the price return of SPY for shares acquired on the first day of a Target Outcome Period and held for the entire Target Outcome Period, subject to a pre-determined upside cap. Because the Fund will acquire shares of the Underlying ETFs in connection with creations of new shares of the Fund and during each semi-annual rebalance and Ramp-Up Period, the Fund typically will not acquire Underlying ETF shares on the first day of a Target Outcome Period. Likewise, the Fund will dispose of shares of the Underlying ETFs in connection with redemptions of shares of the Fund and during each semi-annual rebalance, and such disposals typically will not occur on the last day of a Target Outcome Period. In the event that the Fund acquires Underlying ETF shares after the first day of a Target Outcome Period and the Underlying ETF has risen in value to a level near or at the cap (because the Fund's potential gain will be limited to the difference between the Underlying ETF's NAV on the date the Fund purchases Underlying ETF shares and the cap), there may be little or no ability for the Fund to experience an investment gain on its shares, however, the Fund will remain vulnerable to downside risks. This could be true for all of the Underlying ETFs held by the Fund at a certain point in time severely limiting the Fund's ability to participate in gains during that time. If SPY experiences gains during a Target Outcome Period, an Underlying ETF will not participate in those gains beyond the cap. If the Fund buys Underlying ETF shares when the price exceeds the cap, the Fund will not experience any gain regardless of the performance of SPY.

CASH HOLDINGS RISK. To the extent the Fund holds cash positions, the Fund risks achieving lower returns and potential lost opportunities to participate in market appreciation which could negatively impact the Fund's performance and ability to achieve its investment objective.

COSTS OF BUYING AND SELLING FUND SHARES. Due to the costs of buying or selling Fund Shares, including brokerage commissions imposed by brokers and bid/ask spreads, frequent trading of Fund Shares may significantly reduce investment results and an investment in Fund Shares may not be advisable for investors who anticipate regularly making small investments.

COUNTERPARTY RISK. Underlying ETF transactions involving a counterparty are subject to the risk that the counterparty will not fulfill its obligation to the Underlying ETF. Counterparty risk may arise because of the counterparty's financial condition (i.e., financial difficulties, bankruptcy, or insolvency), market activities and developments, or other reasons, whether foreseen or not. A counterparty's inability to fulfill its obligation may result in significant financial loss to an Underlying ETF and, in turn, the Fund. An Underlying ETF may be unable to recover its investment from the counterparty or may obtain a limited recovery, and/or recovery may be delayed. The OCC acts as guarantor and central counterparty with respect to the FLEX Options. As a result, the ability of an Underlying ETF to meet its objective depends on the OCC being able to meet its obligations. In the unlikely event that the OCC becomes insolvent or is otherwise unable to meet its settlement obligations, an Underlying ETF and, in turn, the Fund could suffer significant losses.

DERIVATIVES RISK. Derivatives are instruments, such as options, futures and forward foreign currency contracts, whose value is derived from that of other assets, rates or indices. The use of derivatives for non-hedging purposes may be considered more speculative than other types of investments. Derivatives can be used for hedging (attempting to reduce risk by offsetting one investment position with another) or non-hedging purposes. Hedging with derivatives may increase expenses, and there is no guarantee that a hedging strategy will work. While hedging can reduce or eliminate losses, it can also reduce or eliminate gains. In addition, derivative instruments are subject to counterparty risk, meaning that the party with whom the Fund enters into a derivative transaction may experience a significant credit event and/or may be unwilling or unable to make timely settlement payments or otherwise honor its obligations. Changes in the value of a derivative may not correlate perfectly with the underlying asset, rate or index, and the Fund could lose more than the principal amount invested.

EQUITY SECURITIES RISK. The securities markets are volatile, and the market prices of the SPY's securities may decline generally. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions. If the market prices of the securities owned by the SPY fall, the value of your investment in the Fund will decline.

FLEX OPTIONS RISK. The Underlying ETFs invest in FLEX Options. Trading FLEX Options involves risks different from, or possibly greater than, the risks associated with investing directly in securities. The Underlying ETFs may experience substantial downside from specific FLEX Option positions and certain FLEX Option positions may expire worthless. The FLEX Options are listed on an exchange; however, no one can guarantee that a liquid secondary trading market will exist for the FLEX Options. In the event that trading in the FLEX Options is limited or absent, the value of the Underlying ETFs' FLEX Options may decrease. In a less liquid market for the FLEX Options, liquidating the FLEX Options may require the payment of a premium (for written FLEX Options) or acceptance of a discounted price (for purchased FLEX Options) and may take longer to complete. A less liquid trading market may adversely impact the value of the FLEX Options and Underlying ETFs' shares and result in the Underlying ETFs and, in turn, the Fund being unable to achieve their investment objective. Less liquidity in the trading of the Underlying ETF's FLEX Options could have an impact on the prices paid or received by the Underlying ETFs for the FLEX Options in connection with creations and redemptions of the Underlying ETF's shares. Depending on the nature of this impact to pricing, an Underlying ETF may be forced to pay more for redemptions (or receive less for creations) than the price at which it currently values the FLEX Options. Such overpayment or under collection may impact the value of the Underlying ETF and whether the Underlying ETF can satisfy its investment objective. Additionally, in a less liquid market for the FLEX Options, the liquidation of a large number of options may more significantly impact the price. A less liquid trading market may adversely impact the value of the FLEX Options and the value of the Underlying ETFs. The trading in FLEX Options may be less deep and liquid than the market for certain other exchange-traded options, non-customized options or other securities.

FLEX OPTIONS VALUATION RISK. The FLEX Options held by the Underlying ETFs will be exercisable at the strike price only on their expiration date. Prior to the expiration date, the value of the FLEX Options will be determined based upon market quotations or using other recognized pricing methods. The FLEX Options are also subject to correlation risk, meaning the value of the FLEX Options does not increase or decrease at the same rate as SPY (although they generally move in the same direction) or its underlying securities. The value of the FLEX Options prior to the expiration date may vary because of factors other than the value of SPY, such as interest rate changes, changing supply and demand, decreased liquidity of the FLEX Options, 7 a change in the actual and perceived volatility of the stock market and SPY and the remaining time to expiration. FLEX Option prices may also be highly volatile and may fluctuate substantially during a short period of time. During periods of reduced market liquidity or in the absence of readily available market quotations for the holdings of the Underlying ETFs, the ability of the Underlying ETFs to value the FLEX Options becomes more difficult and the judgment of the Underlying ETFs' investment adviser (employing the fair value procedures approved by the Board of Trustees of the Trust) may play a greater role in the valuation of the Underlying ETFs' holdings due to reduced availability of reliable objective pricing data. Consequently, while such determinations may be made in good faith, it may nevertheless be more difficult for the Underlying ETFs to accurately assign a daily value. Under those circumstances, the value of the FLEX Options will require more reliance on the investment adviser's judgment than that required for securities for which there is an active trading market. This creates a risk of mispricing or improper valuation of the FLEX Options which could impact the value paid for shares of the Underlying ETFs.

FUND-OF-FUNDS RISK. Shareholders of the Fund will experience investment returns that are different than the investment returns provided by an Underlying ETF. The Fund does not itself pursue a defined outcome strategy, nor does the Fund itself provide a defined downside against SPY losses. Because the Fund will typically not purchase an Underlying ETF on the first day of a Target Outcome Period, it is not likely that the stated outcome of the Underlying ETF will be realized by the Fund. The Fund will be continuously exposed to the investment profiles of each of the Underlying ETFs during their respective Target Outcome Periods. The Fund, with its aggregate exposure to each of the Underlying ETFs, may have investment returns that are inferior to that of any single Underlying ETF or group of Underlying ETFs over any given time period. In between the semi-annual rebalance period of the Index, because the Fund is not equally weighted on a continuous basis, the Fund may be exposed to one or more Underlying ETFs disproportionately when compared to other Underlying ETFs. In such circumstances, the Fund will be subject to the over-weighted performance of such Underlying ETF. As a shareholder in other ETFs, the Fund bears its proportionate share of each ETF's expenses, subjecting Fund shareholders to duplicative expenses.

INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund's shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund's net asset value could be negatively impacted and the Fund's market price may be below the Fund's net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

INFORMATION TECHNOLOGY COMPANIES RISK. SPY invests significantly in information technology companies. Information technology companies produce and provide hardware, software and information technology systems and services. These companies may be adversely affected by rapidly changing technologies, short product life cycles, fierce competition, aggressive pricing and reduced profit margins, the loss of patent, copyright and trademark protections, cyclical market patterns, evolving industry standards and frequent new product introductions. In addition, information technology companies are particularly vulnerable to federal, state and local government regulation, and competition and consolidation, both domestically and internationally, including competition from foreign competitors with lower production costs. Information technology companies also heavily rely on intellectual property rights and may be adversely affected by the loss or impairment of those rights.

LARGE CAPITALIZATION COMPANIES RISK. SPY invests in the securities of large capitalization companies. Large capitalization companies may grow at a slower rate and be less able to adapt to changing market conditions than smaller capitalization companies. Thus, the return on investment in securities of large capitalization companies may be less than the return on investment in securities of small and/or mid capitalization companies. The performance of large capitalization companies also tends to trail the overall market during different market cycles.

MANAGEMENT RISK. The Fund is subject to management risk because it is an actively managed portfolio. In managing the Fund's investment portfolio, the portfolio managers will apply investment techniques and risk analyses that may not produce the desired result. There can be no guarantee that the Fund will meet its investment objective.

MARKET FLUCTUATION TAX RISK. The Fund is acquiring shares of the Underlying ETFs in the open market. When the Fund sells shares of the Underlying ETFs in the open market, the Fund will recognize gain or loss on the disposition of the shares, which could have a negative impact on Fund returns. In addition, note that the Fund may, under certain circumstances, effect a portion of its creations and redemptions for cash rather than in-kind. If the Fund effects redemptions for cash, it may be required to sell shares of the Underlying ETFs in order to obtain the cash needed to distribute redemption proceeds. Any recognized gain on these sales by the Fund will generally cause the Fund to recognize a gain it might not otherwise have recognized, or to recognize such gain sooner than would otherwise be required if it were to distribute such shares only in-kind. The Fund intends to distribute these gains to shareholders to avoid being taxed on this gain at the fund level and otherwise comply with the special tax rules that apply to it. This strategy may cause shareholders to be subject to tax on gains they would not otherwise be subject to, or at an earlier date than if they had made an investment in a different ETF. Moreover, cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. These brokerage fees and taxes, which will be higher than if the Fund sold and redeemed its shares entirely in-kind, will be passed on to those purchasing and redeeming Creation Units in the form of creation and redemption transaction fees. In addition, these factors may result in wider spreads between the bid and the offered prices of the Fund's shares than for ETFs that distribute portfolio securities in-kind. The Fund's use of cash for creations and redemptions could also result in dilution to the Fund and increased transaction costs, which could negatively impact the Fund's ability to achieve its investment objective.

MARKET RISK. The risk that the securities markets will increase or decrease in value is considered market risk and applies to any security. If there is a general decline in the stock or fixed-income market, it is possible your investment may lose value regardless of the individual results of the companies in which the Fund invests.

NEW FUND RISK. The Fund is a recently organized investment company with a limited operating history. As a result, prospective investors have a limited track record or history on which to base their investment decision.

NON-DIVERSIFICATION RISK. The Fund is classified as "non-diversified" under the 1940 Act. As a result, the Fund is only limited as to the percentage of its assets which may be invested in the securities of any one issuer by the diversification requirements imposed by the Internal Revenue Code of 1986, as amended (the "Code"). The Fund may invest a relatively high percentage of its assets in a limited number of issuers. As a result, the Fund may be more susceptible to a single adverse economic or regulatory occurrence affecting one or more of these issuers, experience increased volatility and be highly invested in certain issuers.

OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund's service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund's ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

OPTIONS RISK. The use of options by the Underlying ETFs involves investment strategies and risks different from those associated with ordinary portfolio securities transactions and depends on the ability of the Underlying ETFs' portfolio managers to forecast market movements correctly. The prices of options are volatile and are influenced by, among other things, actual and anticipated changes in the value of the underlying instrument, or in interest or currency exchange rates, including the anticipated volatility, which in turn are affected by fiscal and monetary policies and by national and international political and economic events. The effective use of options by the Underlying ETFs also depends on the Underlying ETFs' ability to terminate option positions at times deemed desirable to do so. There is no assurance that the Underlying ETFs will be able to effect closing transactions at any particular time or at an acceptable price. In addition, there may at times be an imperfect correlation between the movement in values of options and their underlying securities and there may at times not be a liquid secondary market for certain options.

PREMIUM/DISCOUNT RISK. The market price of the Fund's shares will generally fluctuate in accordance with changes in the Fund's net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund's investment advisor cannot predict whether shares will trade below at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund's investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund's shares may become less liquid in response to deteriorating liquidity in the market for the Fund's underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund's shares and their net asset value and the bid/ask spread on the Fund's shares may widen.

SECTOR RISK. To the extent the SPY invests a significant portion of its assets in a particular sector, a greater portion of the Underlying ETF's and Fund's performance may be affected by the general business and economic conditions affecting that sector. Each sector may share economic risk with the broader market, however there may be economic risks specific to each sector. As a result, returns from those sectors may trail returns from the overall stock market, and it is possible that the SPY may underperform the broader market.

SIGNIFICANT EXPOSURE RISK. The Fund intends to generally rebalance its portfolio to equal weight (i.e., 8.33% per Underlying ETF) semi-annually, in connection with the reset of each Underlying ETF. In between such rebalances, market movements in the prices of the Underlying ETFs may result in the Fund having temporary larger exposures to certain Underlying ETFs compared to others. Under such circumstances, the Fund's returns would be more greatly influenced by the returns of the Underlying ETFs with the larger exposures.

SPY EQUITY RISK. Because each Underlying ETF holds FLEX Options that reference SPY, each Underlying ETF has exposure to the equity securities markets. Equity securities prices fluctuate for several reasons, including changes in investors' perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

SPY RISK. Each Underlying ETF invests in FLEX Options that reference SPY, which subjects the Underlying ETFs to certain of the risks of owning shares of an ETF as well as the types of instruments in which SPY invests. The value of SPY will fluctuate over time based on fluctuations in the values of the securities held by SPY, which may be affected by changes in general economic conditions, expectations for future growth and profits, interest rates and the supply and demand for those securities. In addition, ETFs are subject to absence of an active market risk, premium/discount risk and trading issues risk. Brokerage, tax and other expenses may negatively impact the performance of the Underlying ETF and, in turn, the value of the Fund's shares. An ETF that tracks an index may not exactly match the performance of the index due to cash drag, differences between the portfolio of the ETF and the components of the index, expenses and other factors.

TARGET OUTCOME PERIOD RISK. Each Underlying ETF's investment strategy is designed to deliver returns that match the price return of SPY if shares are bought on the day on which the Underlying ETF enters into the FLEX Options (i.e., the first day of a Target Outcome Period) and held until those FLEX Options expire at the end of the Target Outcome Period subject to the cap. Because the Fund will acquire shares of the Underlying ETFs in connection with creations of new shares of the Fund and during each quarterly rebalance, the Fund typically will not acquire Underlying ETF shares on the first day of a Target Outcome Period. Likewise, the Fund will dispose of shares of the Underlying ETFs in connection with redemptions of shares of the Fund and during each quarterly rebalance, and such disposals typically will not occur on the last day of a Target Outcome Period. In the event the Fund acquires shares after the first day of a Target Outcome Period or disposes of shares prior to the expiration of the Target Outcome Period, the value of the Fund's investment in Underlying ETF shares may not be protected against a decline in the value of SPY and may not participate in a gain in the value of SPY for the Fund's investment period.

TAX RISK FROM INVESTMENT IN OTHER INVESTMENT COMPANIES. The Fund has based its analysis of its qualification as a "regulated investment company" ("RIC") as defined by the Code on the belief that its portfolio funds are themselves RICs. If a portfolio fund were to lose its status as a RIC for purposes of the Code, the Fund may fail its requirement to have a diversified portfolio, and, thus, lose its own RIC status. If the Fund did not qualify as a RIC for any taxable year and certain relief provisions were not available, the Fund's taxable income would be subject to tax at the Fund level and to a further tax at the shareholder level when such income is distributed. In such event, in order to requalify for taxation as a RIC, the Fund might be required to recognize unrealized gains, pay substantial taxes and interest and make certain distributions. This would cause investors to incur higher tax liabilities than they otherwise would have incurred and would have a negative impact on Fund returns. In such event, the Fund's Board of Trustees may determine to reorganize or close the Fund or materially change the Fund's investment objective and strategies. In the event that the Fund fails to qualify as a RIC, the Fund will promptly notify shareholders of the implications of that failure.

TRADING ISSUES RISK. Trading in Fund Shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in Fund Shares inadvisable. In addition, trading in Fund Shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange's "circuit breaker" rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund's assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

UNDERLYING ETF CONCENTRATION RISK. An Underlying ETF may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Underlying ETF's investments more than the market as a whole, to the extent that the Underlying ETF's investments are concentrated in the securities and/or other assets of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector, market segment or asset class.

UNDERLYING ETF EXPOSURE RISK. An investment in the Fund may provide returns that are lower than the returns that an investor could achieve by investing in one or more of the Underlying ETFs alone. Additionally, if one or more of the Underlying ETFs has exceeded its cap at the time that you invest in the Fund, you may derive no benefit from the Fund's investment in that Underlying ETF until the next reset of the Underlying ETF. Likewise, if one or more of the Underlying ETFs has decreased in value below its downside protection at the time that you invest in the Fund, you may derive no downside protection from the Fund's investment in that Underlying ETF. See Capped Upside Risk above. As a shareholder in other ETFs, the Fund bears its proportionate share of each ETF's expenses, subjecting Fund shareholders to duplicative expenses. The Fund does not itself pursue a target outcome strategy and does not provide any downside protection against Underlying ETF losses.

UNDERLYING ETF RISK. The Fund's investment in shares of the Underlying ETFs subjects it to the risks of owning the securities held by the Underlying the ETF, as well as the same structural risks faced by an investor purchasing shares of the Fund, including absence of an active market risk, premium/discount risk and trading issues risk. As a shareholder in another ETF, the Fund bears its proportionate share of the ETF's expenses, subjecting Fund shareholders to duplicative expenses.

The following are non-principal risks that generally apply to the Fund:

Cybersecurity Risk. Investment companies, such as the Fund, and their service providers are exposed to operational and information security risks resulting from cyberattacks, which may result in financial losses to the Fund and its shareholders. Cyber-attacks include, among other behaviors, stealing or corrupting data maintained online or digitally, denial of service attacks on websites, "ransomware" that renders systems inoperable until ransom is paid, the unauthorized release of confidential information, or various other forms of cybersecurity breaches. Cyber-attacks affecting the Fund, Calamos Advisors, custodian, transfer agent, distributor, market maker, authorized participants, administrator, intermediaries, trading counterparties, and other third-party service providers may adversely impact the Fund or the companies in which the Fund invests, causing the Fund's investments to lose value or to prevent a shareholder redemption or purchase from clearing in a timely manner.

Investment Management Risk. Whether the Fund achieves its investment objective(s) is significantly impacted by whether the Adviser is able to choose suitable investments for the Fund.

Market Disruption Risk. Certain events have a disruptive effect on securities markets, including but not limited to, terrorist attacks, war and other geopolitical events or catastrophes. The Adviser cannot predict the effect of similar events in the future on the U.S. or foreign economies. Certain securities such as high yield and equity securities tend to be impacted more by these events than other types of securities in terms of price and volatility.

Operational Risk. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund's service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund's ability to meet its investment objective. Although the Fund and the Adviser seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

Recent Market Events. Since the 2008 financial crisis, financial markets throughout the world have experienced periods of increased volatility, depressed valuations, decreased liquidity and heightened uncertainty and turmoil. This turmoil resulted in unusual and extreme volatility in the equity and debt markets, in the prices of individual securities and in the world economy. Events that have contributed to these market conditions include, but are not limited to, major cybersecurity events, geopolitical events (such as wars (including Russia's military invasion of the Ukraine), terror attacks, natural or environmental disasters, country instability, and public health emergencies), measures to address budget deficits, downgrading of sovereign debt, declines in oil and commodity prices, dramatic changes in currency exchange rates, and public sentiment. In addition, many governments and quasi-governmental entities throughout the world have responded to the turmoil with a variety of significant fiscal and monetary policy changes, including, but not limited to, direct capital infusions into companies, new monetary programs and dramatically lower interest rates.

The full extent of the political, economic and legal consequences of Brexit are not yet fully known, and the long-term impact of Brexit on the UK, the EU and the broader global economy may be significant. As a result of the political divisions within the UK and between the UK and the EU that the referendum vote has highlighted and the uncertain consequences of Brexit, the UK and European economies and the broader global economy could be significantly impacted, potentially resulting in increased market volatility and illiquidity, political, economic, and legal uncertainty, and lower economic growth for companies that rely significantly on Europe for their business activities and revenues. Any further exits from the EU, or the possibility of such exits, or the abandonment of the Euro, may cause additional market disruption globally and introduce new legal and regulatory uncertainties.

In addition, policy and legislative changes in the United States and in other countries are changing many aspects of financial regulation. The impact of these changes on the markets, and the practical implications for market participants, may not be fully known for some time. Widespread disease and virus epidemics and pandemics, such as the coronavirus outbreak, could likewise be highly disruptive, adversely affecting individual companies, sectors, industries, markets, currencies, interest and inflation rates, credit ratings, investor sentiment, and other factors affecting the value of the Fund's investments.

Portfolio security holdings disclosure

A description of the Fund's policies and procedures in connection with the disclosure of portfolio security holdings of the Fund are available in the SAI and on the Fund's website, www.calamos.com.

Fund Facts

Who manages the Fund?

Investment Adviser

The Fund is advised by Calamos Advisors LLC ("Calamos Advisors" or the "Adviser"), 2020 Calamos Court, Naperville, Illinois 60563. Calamos Advisors, an investment adviser registered with the SEC effective May 29, 1987, is a wholly owned subsidiary of Calamos Investments LLC ("CILLC"). CILLC's assets under management as of December 31, 2023, were $35 billion ($34 billion of which represented Calamos Advisors' assets under management). Calamos Asset Management, Inc. ("CAM") is the sole manager of CILLC. As of December 31, 2023, approximately 22% of the outstanding interests of CILLC was owned by CAM and the remaining approximately 78% of CILLC was owned by Calamos Partners LLC ("CPL") and John P. Calamos, Sr. CAM was owned by John P. Calamos, Sr. and John S. Koudounis, and CPL was owned by John S. Koudounis and Calamos Family Partners, Inc. ("CFP"). CFP was beneficially owned by members of the Calamos family, including John P. Calamos, Sr.

Subject to the overall authority of the Board of Trustees, Calamos Advisors provides continuous investment supervision and management to the Fund under a management agreement and also furnishes office space, equipment and management personnel. For these services, the Fund pays Calamos Advisors a fee based on its average daily net assets, which is accrued daily and paid on a quarterly basis. The Fund will pay fees (before any reimbursement) under the management agreement in the following amounts as a percentage of its average net assets:

ETF			FEES
Calamos Laddered S&P 500 Structured Alt Protection ETF			0.10	%

Out of this management fee, Calamos Advisors pays substantially all expenses of the Fund, including the cost of transfer agency, custody, fund administration, legal, audit and other service and license fees, except for distribution and service fees payable pursuant to a Rule 12b-1 plan, if any, acquired fund fees and expenses brokerage commissions and other expenses connected with the execution of portfolio transactions, taxes, interest, and extraordinary expenses.

At a meeting held on August 12, 2024, the Board of Trustees approved the Investment Management Agreement for the Fund. A discussion regarding the basis for the Board's approval of the Investment Management Agreement on behalf of the Fund will be included in the first shareholder report that covers the period in which the Fund commences operations.

Portfolio Managers

David O'Donohue. David O'Donohue joined Calamos Advisors in August 2014 and is a Sr. Co-Portfolio Manager (since February 2024) and Co-Head of Alternative Strategies (since July 2024) and was a Co-Portfolio Manager from September 2015 through January 2024. Between March 2013 and August 2014, he was a Trader at Forty4 Asset Management LLC/Hard8 Futures LLC. Prior thereto, Mr. O'Donohue was a Portfolio Manager at Chicago Fundamental Investment Partners LLC from February 2009 to November 2012.

Jimmy Young. Jimmy Young joined Calamos Advisors in June 2003 and has been a Co-Portfolio Manager since February 2019. Between February 2018 and February 2019, he was an Assistant Portfolio Manager. Prior thereto, he was a senior strategy analyst from September 2015 to February 2018. Between July 2013 and August 2015, he was a strategy analyst.

Eli Pars. Eli Pars joined Calamos Advisors in May 2013 and has been Co-CIO, Co-Head of Alternative Strategies (since July 2024; previously served as Head of Alternative Strategies from September 2015 to June 2024) and Co-Head of Convertible Strategies, as well as a Senior Co-Portfolio Manager since September 2015. Between May 2013 and September 2015, he was a Co-Portfolio Manager. Previously, he was a Portfolio Manager at Chicago Fundamental Investment Partners from February 2009 until November 2012.

Jason Hill. Jason Hill joined Calamos Advisors in March 2004 and has been a Sr. Co-Portfolio Manager since February 2024 and was a Co-Portfolio Manager from June 2014 through January 2024. Between August 2013 and June 2014, he was a Senior Strategy Analyst. Previously, he was a Portfolio Administrator.

Anthony Vecchiolla. Anthony Vecchiolla joined Calamos Advisors in May 2014 and since February 2023 has been a Co-Portfolio Manager. Previously, he was a Research Associate from May 2014 to August 2015, a Research Analyst from September 2015 to February 2020, a Senior Research Analyst from February 2020 to February 2021, and an Assistant Portfolio Manager from February 2021 to January 2023.

Fund Facts

The Fund's SAI provides additional information about each portfolio manager, including other accounts they manage, their ownership in the Calamos Family of Funds and their compensation.

Management Approach

Calamos Advisors employs a "team of teams" approach to portfolio management, led by the Global CIO and our CIO team consisting of 5 Co-CIOs with specialized areas of investment expertise. The Global CIO and Co-CIO team are responsible for oversight of investment team resources, investment processes, performance and risk. As heads of investment verticals, Co-CIOs manage investment team members and, along with Co- Portfolio Managers and Associate Portfolio Managers, have day-to-day portfolio oversight and construction responsibilities of their respective investment strategies. While investment research professionals within each Co-CIO's team are assigned specific strategy responsibilities, they also provide support to other investment team verticals, creating deeper insights across a wider range of investment strategies. The combination of specialized investment teams with cross-team collaboration results in what we call our team of teams approach.

This team of teams approach is further reflected in the composition of Calamos Advisors' Investment Committee, made up of the Global CIO, the Co-CIO team, and the Global Head of Trading. Other members of the investment team participate in Investment Committee meetings in connection with specific investment related issues or topics as deemed appropriate.

The structure and composition of the Investment Committee results in a number of benefits, as it:

• Leads to broader perspective on investment decisions: multiple viewpoints and areas of expertise feed into consensus;

• Promotes collaboration between teams; and

• Functions as a think tank with the goal of identifying ways to outperform the market on a risk-adjusted basis.

The objectives of the Investment Committee are to:

• Form the firm's top-down macro view, market direction, asset allocation, and sector/country positioning.

• Establish firm-wide secular and cyclical themes for review.

• Review firm-wide and portfolio risk metrics, recommending changes where appropriate.

• Review firm-wide, portfolio and individual security liquidity constraints.

• Evaluate firm-wide and portfolio investment performance.

• Evaluate firm-wide and portfolio hedging policies and execution.

• Evaluate enhancements to the overall investment process.

How to Buy and Sell Shares

Fund Shares are listed for secondary trading on the Exchange under the symbol [TO COME] and individual Fund Shares may only be purchased and sold in the secondary market through a broker-dealer. The Exchange and secondary markets are closed on weekends and also are generally closed on the following holidays: New Year's Day, Dr. Martin Luther King, Jr. Day, Presidents' Day, Good Friday, Memorial Day (observed), Juneteenth, Independence Day, Labor Day, Thanksgiving Day and Christmas Day. The Exchange may close early on the business day before certain holidays and on the day after Thanksgiving Day. Exchange holiday schedules are subject to change without notice. If you buy or sell Fund Shares in the secondary market, you will pay the secondary market price for Fund Shares. In addition, you may incur customary brokerage commissions and charges and may pay some or all of the spread between the bid and the offered price in the secondary market on each leg of a round trip (purchase and sale) transaction.

The trading prices of Fund Shares will fluctuate continuously throughout trading hours based on market supply and demand rather than the relevant Fund's net asset value, which is calculated at the end of each business day.

Fund Shares will trade on the Exchange at prices that may be above (i.e., at a premium) or below (i.e., at a discount), to varying degrees, the daily net asset value of Fund Shares. The trading prices of Fund Shares may deviate significantly from the Fund's net asset value during periods of market volatility. Given, however, that Fund Shares can be issued and redeemed daily in Creation Units, the Adviser believes that large discounts and premiums to net asset value should not be sustained over long periods.

Fund Facts

Authorized Participants may acquire shares directly from the Fund, and Authorized Participants may tender their shares for redemption directly to the Fund, at NAV per share only in Creation Units. Purchases and redemptions directly with the Fund must follow the Fund's procedures, which are described in the SAI.

The Fund may liquidate and terminate at any time without shareholder approval.

Book Entry

Fund Shares are held in book-entry form, which means that no stock certificates are issued. The Depository Trust Company ("DTC") or its nominee is the record owner of all outstanding Shares of the Fund and is recognized as the owner of all Shares for all purposes.

Investors owning Fund Shares are beneficial owners as shown on the records of DTC or its participants. DTC serves as the securities depository for all Fund Shares. Participants in DTC include securities brokers and dealers, banks, trust companies, clearing corporations and other institutions that directly or indirectly maintain a custodial relationship with DTC. As a beneficial owner of Fund Shares, you are not entitled to receive physical delivery of stock certificates or to have Fund Shares registered in your name, and you are not considered a registered owner of Fund Shares. Therefore, to exercise any right as an owner of Fund Shares, you must rely upon the procedures of DTC and its participants. These procedures are the same as those that apply to any other securities that you hold in book entry or "street name" form.

Fund Share Trading Prices

The trading prices of Shares of the Fund on the Exchange may differ from the Fund's daily NAV. Market forces of supply and demand, economic conditions and other factors may affect the trading prices of Shares of the Fund.

The approximate value of Shares of the Fund, an amount representing on a per share basis the sum of the current market price of the cash or securities, as applicable, accepted by the Fund in exchange for Shares of the Fund and an estimated cash component, if any, is disseminated every 15 seconds throughout the trading day through the facilities of the Consolidated Tape Association. This approximate value should not be viewed as a "real-time" update of the NAV per Share of the Fund because the approximate value may not be calculated in the same manner as the NAV, which is computed once a day, generally at the end of the business day. The Fund is not involved in, or responsible for, the calculation or dissemination of the approximate value of the Fund Shares and the Fund does not make any warranty as to its accuracy.

Frequent Purchases and Redemptions of Fund Shares

Shares of the Fund may be purchased and redeemed directly from the Fund only in Creation Units by Authorized Participants. The vast majority of trading in Shares of the Fund occurs on the secondary market, and does not involve the Fund directly. In-kind purchases and redemptions of Creation Units by Authorized Participants and cash trades on the secondary market are unlikely to cause many of the harmful effects of frequent purchases and/or redemptions of Fund Shares. Cash purchases and/or redemptions of Creation Units, however, can result in disruption of portfolio management, dilution to the Fund and increased transaction costs, which could negatively impact the Fund's ability to achieve its investment objective, and may lead to the realization of capital gains. These consequences may increase as the frequency of cash purchases and redemptions of Creation Units by Authorized Participants increases. However, direct trading by Authorized Participants is critical to ensuring that Fund Shares trade at or close to NAV.

The Fund impose no restrictions on the frequency of purchases and redemptions ("market timing"). To minimize these potential consequences of frequent purchases and redemptions of Fund Shares, the Fund employs fair valuation pricing, and imposes transaction fees on purchases and redemptions of Creation Units to cover the custodial and other costs the Fund incurs in effecting trades. In addition, the Adviser monitors trades by Authorized Participants for patterns of abusive trading and the Fund reserves the right to not accept orders from Authorized Participants that the Adviser has determined may be disruptive to the management of the Fund, or otherwise are not in the best interests of the Fund. For these reasons, the Board has not adopted policies and procedures with respect to frequent purchases and redemptions of Fund Shares. The Trust's policies and procedures regarding frequent purchases and redemptions may be modified by the Board of Trustees at any time.

CALAMOS LADDERED S&P 500^® STRUCTURED ALT PROTECTION ETF^TM

Fund Facts

The Trust's policies and procedures prohibit the practice of any officer or employee of the Trust, a Trust investment adviser (including any sub-adviser), the distributor, custodian, or transfer agent, or other affiliated person of the Trust placing orders to purchase or redeem shares of a series of the Trust after the designated time as of which the Fund calculates its NAV (i.e., "late trading").

Distribution and Service Plan

The Fund has adopted a distribution and service plan ("Plan") pursuant to Rule 12b-1 under the 1940 Act. Under the Plan, the Fund is authorized to pay distribution fees to the Distributor and other firms that provide distribution and shareholder services ("Service Providers"). If a Service Provider provides such services, the Fund may pay fees at an annual rate not to exceed 0.25% of average daily net assets, pursuant to Rule 12b-1 under the 1940 Act.

No distribution or service fees are currently paid by the Fund, however, and there are no current plans to impose these fees. In the event Rule 12b-1 fees are charged, over time they would increase the cost of an investment in the Fund because they would be paid on an ongoing basis.

Fund Website and Disclosure of Portfolio Holdings

The Trust maintains a website for the Fund at www.calamos.com. Among other things, this website includes this Prospectus and the SAI, and will include the Fund's holdings, the Fund's last annual and semi-annual reports (when available), pricing information about Fund Shares trading on the Exchange, daily NAV calculations and a historical comparison of the trading prices to NAV.

Each day the Fund is open for business, the Trust publicly disseminates the Fund's full portfolio holdings as of the close of the previous day through its website at www.calamos.com. A description of the Trust's policies and procedures with respect to the disclosure of the Fund's portfolio holdings is available in the Fund's SAI.

Dividends, Other Distributions and Taxes

Fund Distributions

The Fund distributes its net realized capital gains, if any, to shareholders annually. Ordinarily, dividends from net investment income, if any, are declared and paid at least annually by the Fund.

Distributions in cash may be reinvested automatically in additional whole Fund Shares only if the broker through whom you purchased Fund Shares makes such option available. The Fund realizes capital gains or losses whenever it sells securities. Net long-term capital gains are distributed to shareholders as "capital gain dividends."

Brokers may make available to their customers who own Fund Shares the DTC book-entry dividend reinvestment service. To determine whether the dividend reinvestment service is available and whether there is a commission or other charge for using this service, consult your broker. Brokers may require Fund shareholders to adhere to specific procedures and timetables. If this service is available and used, dividend distributions of both income and net realized gains will be automatically reinvested in additional whole Fund Shares of the Fund purchased in the secondary market. Without this service, investors would receive their distributions in cash.

Taxes

As with any investment, you should consider how your investment in Fund Shares of the Fund will be taxed. The tax information in this prospectus is provided only as general information. This section is current as of the date of this prospectus. Tax laws and interpretations change frequently, and these summaries do not describe all of the tax consequences to all taxpayers. For example, these summaries generally do not describe your situation if you are a corporation, a non-U.S. person, a broker-dealer, or other investor with special circumstances. However, with respect to certain tax issues, the summaries describe the general tax treatment of certain distributions made to corporations and non-U.S. persons. In addition, this section does not describe your state, local or non-U.S. tax consequences You should consult your own tax advisor about the tax consequences of an investment in Fund Shares.

Fund distributions to you and the sale or redemption of your Fund Shares will have tax consequences to you. Such consequences may be different if you hold your Fund Shares through a tax-exempt entity or tax-advantaged retirement account, such as an individual retirement account or 401(k) plan.

PROSPECTUS |

Fund Facts

The Fund intends to elect to be treated, and intends to qualify each year, as a regulated investment company (a "RIC") under the Code. As a RIC, the Fund is generally not subject to corporate-level U.S. federal income tax on any net ordinary income or capital gains that are timely distributed to shareholders. However, the Fund's failure to qualify as a RIC or to meet minimum distribution requirements would result (if certain relief provisions were not available) in corporate-level taxation and, consequently, a reduction in amounts available for distribution to shareholders.

The Fund may enter into option agreements with the same counterparty but has taken the position that the option agreements are separate agreements. Under general tax principles, the Fund would not accrue income on separate option agreements during the term of the agreements. However, if the agreements are treated as one agreement, the Fund might be required to accrue income and make annual distributions of income. If the Fund is required to accrue income, but does not distribute the income to shareholders, the Fund may fail to qualify as a RIC. In addition, if the agreements are treated as one agreement, the Fund may fail either or both of the RIC income and diversification tests.

For purposes of the diversification tests, the identification of the issuer (or, in some cases, issuers) of a particular investment can depend on the terms and conditions of such investment. In particular, there is no published Internal Revenue Service guidance or case law on how to determine the "issuer" of various derivatives that the Fund may enter into. Therefore, there is a risk that the Fund will not meet the Code's diversification requirements and will not qualify, or will be disqualified, as a RIC.

Taxes on Distributions

Distributions by the Fund generally are taxable to you as ordinary income or capital gains. Distributions are subject to federal income tax, whether received in cash or reinvested in additional Fund shares or shares of another fund, and may be subject to state or local taxes. Distributions of the Fund's "investment company taxable income" generally will be taxable as ordinary income to the extent of the Fund's current or accumulated earnings and profits. Notwithstanding the foregoing, distributions that are attributable to "qualified dividends" received by the Fund may be eligible to be taxed at long-term capital gains rates, as long as the Fund and the shareholder meet certain holding period requirements. It is not anticipated that the Fund will have qualified dividend income.

Distributions of the Fund's net capital gain that are properly reported by the Fund as "capital gain dividends" will generally be taxable to you as long-term capital gains, currently at a maximum rate of 20%, regardless of your holding period in the Fund's Shares. The Fund's option strategy is likely to reduce the amount of dividends that might otherwise qualify as capital gains dividends. Distributions in excess of the Fund's current and accumulated earnings and profits first will reduce your adjusted tax basis in your Fund Shares and, after the adjusted basis is reduced to zero, will constitute capital gain. Such capital gain will be long-term capital gain and thus, will be taxed at a maximum rate of 20%, if the distributions are attributable to Fund Shares that you have held for more than one year.

Certain non-corporate taxpayers will also be subject to a 3.8% U.S. federal Medicare contribution tax with respect to the lesser of (1) their "net investment income" or (2) the excess of their "modified adjusted gross income" over a threshold amount ($200,000 for single taxpayers and $250,000 for taxpayers who are married and filing jointly).

Corporate shareholders of the Fund are generally eligible for a dividends-received deduction with respect to ordinary income dividends (but not capital gain dividends) properly designated as eligible for such deduction by the Fund, as long as the Fund and the corporate shareholder meet certain holding period and other requirements. It is not anticipated that the Fund will make distributions eligible for the dividend-received deduction.

Under a dividend reinvestment service, you may have the option to have all cash distributions automatically reinvested in additional Fund Shares. Any distributions reinvested under such a service will nevertheless be taxable to you as described above.

You will have an adjusted basis in the additional Fund Shares purchased through such a reinvestment service equal to the amount of the reinvested distribution plus the amount of any fees charged for the transaction. The additional Fund Shares will have a holding period commencing on the day following the day on which they are credited to your account.

CALAMOS LADDERED S&P 500^® STRUCTURED ALT PROTECTION ETF^TM

Fund Facts

A distribution will reduce the Fund's NAV per Share and generally will be taxable to you as ordinary income or capital gain even if it is paid from income or gains earned by the Fund before you invested in the Fund. From an investment standpoint, such a distribution constitutes a return of capital. However, from a tax standpoint, it constitutes taxable income. In general, distributions are subject to federal income tax as of the date of payment. However, distributions paid in January will be treated as paid on December 31 of the prior year if they were declared and payable to shareholders of record on a date in October, November or December of the prior year.

The Fund's transactions in derivatives, as well as any of its hedging, short sale, securities loan or similar transactions may be subject to one or more special tax rules. These rules may affect whether gains and losses recognized by the Fund are treated as ordinary or capital, accelerate the recognition of income or gains to the Fund, defer losses to the Fund, and cause adjustments in the holding periods of the Fund's securities, thereby affecting whether capital gains and losses are treated as short-term or long-term. These rules could therefore affect the amount, timing and/or character of distributions to shareholders and thus taxes payable by shareholders.

The FLEX Options included in the Fund's portfolio are exchange-traded options. Under Section 1256 of the Code, certain types of exchange-traded options are treated as if they were sold (i.e., "marked to market") at the end of each year. The Fund does not believe that some of the positions in FLEX Options held by the Fund will be subject to Section 1256, which means that the positions will not be marked to market, but the positions will be subject to the straddle rules.

The straddle rules may affect the character of gains (or losses) realized by the Fund, and losses realized by the Fund on positions that are part of a straddle may be deferred under the straddle rules, rather than being taken into account in calculating taxable income for the taxable year in which the losses are realized. In addition, certain carrying charges (including interest expense) associated with positions in a straddle may be required to be capitalized rather than deducted currently. Certain elections that the Fund may make with respect to its straddle positions may also affect the amount, character and timing of the recognition of gains or losses from the affected positions.

The tax consequences of straddle transactions to the Fund are not entirely clear in all situations under currently available authority. The straddle rules may increase the amount of short-term capital gain realized by the Fund, which is taxed as ordinary income when distributed to U.S. shareholders in a non-liquidating distribution. Because application of the straddle rules may affect the character of gains or losses, defer losses and/or accelerate the recognition of gains or losses from the affected straddle positions, if the Fund makes a non-liquidating distribution of its short-term capital gain, the amount which must be distributed to U.S. shareholders as ordinary income may be increased substantially as compared to the Fund that did not engage in such transactions.

You may be subject to federal back-up withholding tax, if you do not provide the Fund with a taxpayer identification number (for an individual, a social security number) and make other required certifications, or the Internal Revenue Service informs the Fund that your tax identification number is incorrect. Backup withholding is not an additional tax. You may claim the amount withheld as a credit on your federal income tax return, provided you furnish the appropriate information to the Internal Revenue Service.

Taxes When Shares are Sold

Any capital gain or loss realized upon a sale of Fund Shares is generally treated as long-term capital gain or loss if you have held the Fund Shares for more than one year and as short-term capital gain or loss if you have held the Fund Shares for one year or less. The ability to deduct capital losses realized on a sale of Fund Shares may be limited.

Taxes on Purchase and Redemption of Creation Units

An Authorized Participant that exchanges equity securities for Creation Units will generally recognize a gain or a loss on the exchange. Any such gain or loss will be equal to the difference between the market value of the Creation Units at the time of the exchange, plus (or minus) the cash amount received (or paid), and such Authorized Participant's aggregate basis in the securities surrendered. A person who redeems Creation Units for equity securities will generally recognize a gain or loss equal to the difference between the aggregate market value of the securities received plus (or minus) any cash received (or paid), and such person's basis in the Creation Units redeemed. The Internal Revenue Service, however, may assert that a loss realized upon an exchange of securities for Creation Units cannot be deducted currently under the rules governing "wash sales," or on the basis that there has been no significant change in the Authorized Participant's economic position with respect to such Creation Units. Persons exchanging securities should consult their own tax advisor with respect to the applicability of the wash sale rules and the availability and timing of a deduction for any loss. In addition, when a regulated investment company redeems a shareholder in kind, the regulated investment company generally is not required to recognize taxable gains in respect of the portfolio securities it distributes to the redeeming shareholder. However, the Fund may be required to recognize taxable gain on the distribution of certain securities, and the Internal Revenue Service may assert that the Fund must recognize taxable gain in respect of certain other securities that the Fund distributes to a shareholder in exchange for Creation Units, which may increase the amount of taxable gains that the Fund would otherwise be required to distribute in order to maintain its qualification as a regulated investment company and avoid the Fund-level tax.

PROSPECTUS |

Fund Facts

Any capital gain or loss realized upon a redemption of Creation Units is generally treated as long-term capital gain or loss if the Creation Units have been held for more than one year and as short-term capital gain or loss if the Creation Units have been held for one year or less. If you purchase or redeem Creation Units, you will be sent a confirmation statement showing how many Fund Shares you purchased or sold and at what price.

Authorized Participants that are dealers may be subject to special tax rules and should consult their own tax advisors regarding the tax consequences of purchasing and redeeming Creation Units in their capacity as dealers.

Treatment of Fund Expenses

Expenses incurred and deducted by the Fund will generally not be treated as income taxable to you.

Non-U.S. Investors

If you are a non-U.S. investor (i.e., an investor other than a U.S. citizen or resident or a U.S. corporation, partnership, estate or trust), you should be aware that, generally, subject to applicable tax treaties, distributions from the Fund will be characterized as dividends for U.S. federal income tax purposes (other than dividends which the Fund properly reports as capital gain dividends) and will be subject to U.S. federal income taxes, including withholding taxes, subject to certain exceptions described below. However, distributions received by a non-U.S. investor from the Fund that are properly reported by the Fund as capital gain dividends may not be subject to U.S. federal income taxes, including withholding taxes, provided that the Fund makes certain elections and certain other conditions are met. The Fund's option strategy is likely to reduce the amount of distributions otherwise eligible to be capital gains dividends.

Distributions may be subject to a U.S. withholding tax of 30% in the case of distributions to (i) certain non-U.S. financial institutions that have not entered into an agreement with the U.S. Treasury to collect and disclose certain information and are not resident in a jurisdiction that has entered into such an agreement with the U.S. Treasury and (ii) certain other non-U.S. entities that do not provide certain certifications and information about the entity's U.S. owners. The Internal Revenue Service and the Department of Treasury have issued proposed regulations providing that these withholding rules will not be applicable to the gross proceeds of share redemptions or capital gains dividends that the Fund pays.

Other Tax Matters

The foregoing is only a summary of certain federal income tax considerations of investing in the Fund under current law, which is subject to change in the future. Shareholders who are not U.S. persons within the meaning of the Code, such as non-resident aliens, foreign trusts or estates, or foreign corporations or partnerships may be subject to different U.S. federal income tax treatment.

You may also be subject to state and local taxes on distributions paid by the Fund, and sales and redemptions of Fund shares. You should consult your tax advisor for further information regarding federal, state, local and/or foreign tax consequences relevant to your specific tax situation. More information about taxes can be found in the Fund's SAI.

Net Asset Value

The NAV of shares is determined at the close of regular trading on the New York Stock Exchange (normally 4:00 p.m. Eastern Time) on each day the New York Stock Exchange ("NYSE") is open. NAV is computed by determining the aggregate market value of all assets of the Fund, less its liabilities, divided by the total number of shares outstanding ((assets-liabilities)/number of shares = NAV). The NYSE is closed on weekends and New Year's Day, Martin Luther King, Jr. Day, Presidents' Day, Good Friday, Memorial Day, Juneteenth National Independence Day, Independence Day, Labor Day, Thanksgiving Day and Christmas Day. The NAV takes into account the expenses and fees of the Fund, including management, administration, and distribution fees, which are accrued daily. The determination of NAV for the Fund for a particular day is applicable to all applications for the purchase of shares, as well as all requests for the redemption of shares, received by the Fund (or an authorized broker or agent, or its authorized designee) before the close of trading on the NYSE on that day.

CALAMOS LADDERED S&P 500^® STRUCTURED ALT PROTECTION ETF^TM

Fund Facts

Generally, securities traded or dealt in upon one or more securities exchanges (whether domestic or foreign) for which market quotations are readily available and not subject to restrictions against resale shall be valued at the last quoted sales price on the primary exchange or, in the absence of a sale on the primary exchange, at the mean between the current bid and ask prices on such exchange. Securities primarily traded in the National Association of Securities Dealers' Automated Quotation System ("NASDAQ") National Market System for which market quotations are readily available shall be valued using the NASDAQ official closing price. Securities that are not traded or dealt in any securities exchange (whether domestic or foreign) and for which over-the-counter market quotations are readily available generally shall be valued at the last sale price or, in the absence of a sale, at the mean between the current bid and ask price on such over-the-counter market. Debt securities not traded on an exchange may be valued at prices supplied by a pricing agent (s) based on broker or dealer supplied valuations or matrix pricing, a method of valuing securities by reference to the value of other securities with similar characteristics, such as rating, interest rate and maturity. Futures, swaps and options contracts listed for trading on a futures or options exchange or board of trade for which market quotations are generally available are valued at the last quoted sale price, or, in the absence of a sale, at the mean of the last bid and ask price. Total return swaps on exchange-listed securities are valued at the last quoted sale price, or, in the absence of a sale, at the mean of the last bid and ask price.

Securities held by the Fund are valued in accordance with policies and procedures established by the Adviser pursuant to Rule 2a-5 under the 1940 Act and approved by and subject to the oversight of the Board of Trustees ("Valuation Procedures"). If market quotations are not readily available, securities or other assets will be valued at their fair value as determined in good faith by the Adviser in accordance with procedures approved by the Board and evaluated by the Board as to the reliability of the fair value method used. In these cases, the Fund's NAV will reflect certain portfolio securities' fair values rather than their market prices. Fair value pricing involves subjective judgments, and it is possible that the fair value determined for a security or other asset may be materially different than the value that could be realized upon the sale of that security or other asset. The fair value prices can differ from market prices. The Board of Trustees has designated Calamos Advisors as "valuation designee" for the Fund. The valuation designee is responsible for determining the value of the Fund's investments. The designee may also enlist third party consultants such as an audit firm or financial officer of a security issuer on an as-needed basis to assist in determining a security-specific fair value. The Board reviews and ratifies the execution of this process and the resultant fair value prices at least quarterly to ensure the process produces reliable results.

The Fund may use independent pricing services to assist in calculating the value of the Fund's securities or other assets.

With respect to any portion of the Fund's assets that are invested in one or more open-end management investment companies registered under the 1940 Act, the Fund's net asset value is calculated based upon the net asset values of those open-end management investment companies, and the prospectuses for these companies explain the circumstances under which those companies will use fair value pricing and the effects of using fair value pricing.

Fund Service Providers

State Street Bank and Trust Company ("State Street"), located at One Congress Street, Suite 1, Boston, Massachusetts 02114-2016, serves as the Fund's administrator, custodian, fund accounting and transfer agent.

Calamos Financial Services LLC ("CFS") serves as the distributor of Creation Units for the Fund on an agency basis. The Distributor does not maintain a secondary market in Fund Shares.

Ropes & Gray LLP, located at 191 North Wacker Drive, 32^nd Floor, Chicago, IL 60606, serves as legal counsel to the Trust.

PROSPECTUS |

Fund Facts

Premium/Discount Information

Information showing the number of days the market price of the Fund Shares was greater (at a premium) and less (at a discount) than the Fund's NAV for the most recently completed calendar year, and the most recently completed calendar quarters since that year (or the life of the Fund, if shorter), is available at www.calamos.com.

Investments in Other Investment Companies

Generally, investments in ETFs are subject to statutory limitations prescribed by the 1940 Act. These limitations include a prohibition on the Fund acquiring more than 3% of the voting shares of any other investment company, a prohibition on investing more than 5% of the Fund's total assets in the securities of any one investment company or more than 10% of its total assets, in the aggregate, in investment company securities.

The Fund will invest in the Underlying ETFs beyond these statutory limitations in reliance on Section 12(d)(1)(G) of the 1940 Act.

CALAMOS LADDERED S&P 500^® STRUCTURED ALT PROTECTION ETF^TM

Financial Highlights

The Fund is new and has no performance history as of the date of this prospectus. Financial information is therefore not available.

PROSPECTUS |

Other Information

Continuous Offering

The method by which Creation Units of Fund Shares are created and traded may raise certain issues under applicable securities laws. Because new Creation Units of Fund Shares are issued and sold by the Fund on an ongoing basis, a "distribution," as such term is used in the Securities Act of 1933, as amended (the "Securities Act"), may occur at any point. Broker-dealers and other persons are cautioned that some activities on their part may, depending on the circumstances, result in their being deemed participants in a distribution in a manner which could render them statutory underwriters and subject them to the prospectus delivery requirements and liability provisions of the Securities Act. For example, a broker-dealer firm or its client may be deemed a statutory underwriter if it takes Creation Units after placing an order with the Distributor, breaks them down into constituent Fund Shares and sells the Fund Shares directly to customers or if it chooses to couple the creation of a supply of new Fund Shares with an active selling effort involving solicitation of secondary market demand for Fund Shares. A determination of whether one is an underwriter for purposes of the Securities Act must take into account all the facts and circumstances pertaining to the activities of the broker-dealer or its client in the particular case, and the examples mentioned above should not be considered a complete description of all the activities that could lead to a characterization as an underwriter.

Broker-dealer firms should also note that dealers who are not "underwriters" but are effecting transactions in Fund Shares, whether or not participating in the distribution of Fund Shares, are generally required to deliver a prospectus. This is because the prospectus delivery exemption in Section 4(3) of the Securities Act is not available in respect of such transactions as a result of Section 24(d) of the 1940 Act. As a result, broker-dealer firms should note that dealers who are not "underwriters" but are participating in a distribution (as contrasted with engaging in ordinary secondary market transactions) and thus dealing with the Fund Shares that are part of an overallotment within the meaning of Section 4(3)(C) of the Securities Act, will be unable to take advantage of the prospectus delivery exemption provided by Section 4(3) of the Securities Act. For delivery of prospectuses to exchange members, the prospectus delivery mechanism of Rule 153 under the Securities Act is only available with respect to transactions on a national exchange.

Disclaimer

The "S&P 500^®" is a product of S&P Dow Jones Indices LLC or its affiliates ("SPDJI") and has been licensed for use by Calamos Advisors LLC ("Calamos Advisors"). Standard & Poor's^® and S&P^® are registered trademarks of Standard & Poor's Financial Services LLC ("S&P") and Dow Jones^® is a registered trademark of Dow Jones Trademark Holdings LLC ("Dow Jones"). Calamos Laddered S&P 500 Structured Alt Protection ETF (the "Fund") is not sponsored, endorsed, sold or promoted by SPDJI, Dow Jones, S&P, any of their respective affiliates (collectively, "S&P Dow Jones Indices"). S&P Dow Jones Indices makes no representation or warranty, express or implied, to the owners of the Fund or any member of the public regarding the advisability of investing in securities generally or in the Fund particularly or the ability of the S&P 500^® to track general market performance. S&P Dow Jones Indices' only relationship to Calamos Advisors with respect to the S&P 500^® is the licensing of the Index and certain trademarks, service marks and/or trade names of S&P Dow Jones Indices and/or its licensors. The S&P 500^® is determined, composed and calculated by S&P Dow Jones Indices without regard to Calamos Advisors or the Fund. S&P Dow Jones Indices has no obligation to take the needs of Calamos or the owners of the Fund into consideration in determining, composing or calculating the S&P 500^®. S&P Dow Jones is not responsible for and has not participated in the determination of the prices, and amount of the Fund or the timing of the issuance or sale of the Fund or in the determination or calculation of the equation by which the Fund is to be converted into cash, surrendered or redeemed, as the case may be. S&P Dow Jones Indices has no obligation or liability in connection with the administration, marketing or trading of the Fund. There is no assurance that investment products based on the S&P 500^® will accurately track index performance or provide positive investment returns. S&P Dow Jones Indices LLC is not an investment advisor. Inclusion of a security within an index is not a recommendation by S&P Dow Jones Indices to buy, sell, or hold such security, nor is it considered to be investment advice.

CALAMOS LADDERED S&P 500^® STRUCTURED ALT PROTECTION ETF^TM

Other Information

S&P DOW JONES INDICES DOES NOT GUARANTEE THE ADEQUACY, ACCURACY, TIMELINESS AND/OR THE COMPLETENESS OF THE S&P 500^® OR ANY DATA RELATED THERETO OR ANY COMMUNICATION, INCLUDING BUT NOT LIMITED TO, ORAL OR WRITTEN COMMUNICATION (INCLUDING ELECTRONIC COMMUNICATIONS) WITH RESPECT THERETO. S&P DOW JONES INDICES SHALL NOT BE SUBJECT TO ANY DAMAGES OR LIABILITY FOR ANY ERRORS, OMISSIONS, OR DELAYS THEREIN. S&P DOW JONES INDICES MAKES NO EXPRESS OR IMPLIED WARRANTIES, AND EXPRESSLY DISCLAIMS ALL WARRANTIES, OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE OR USE OR AS TO RESULTS TO BE OBTAINED BY CALAMOS ADVISORS, OWNERS OF THE FUND, OR ANY OTHER PERSON OR ENTITY FROM THE USE OF THE S&P 500^® OR WITH RESPECT TO ANY DATA RELATED THERETO. WITHOUT LIMITING ANY OF THE FOREGOING, IN NO EVENT WHATSOEVER SHALL S&P DOW JONES INDICES BE LIABLE FOR ANY INDIRECT, SPECIAL, INCIDENTAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES INCLUDING BUT NOT LIMITED TO, LOSS OF PROFITS, TRADING LOSSES, LOST TIME OR GOODWILL, EVEN IF THEY HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES, WHETHER IN CONTRACT, TORT, STRICT LIABILITY, OR OTHERWISE. THERE ARE NO THIRD PARTY BENEFICIARIES OF ANY AGREEMENTS OR ARRANGEMENTS BETWEEN S&P DOW JONES INDICES AND CALAMOS ADVISORS, OTHER THAN THE LICENSORS OF S&P DOW JONES INDICES.

Summary of Certain Provisions of the Second Amended and Restated Trust Instrument

The summary below is a synopsis of certain provisions contained in the Trust's Second Amended and Restated Trust Instrument (the "Trust Instrument"). Shareholders should refer to the Trust Instrument for further information. Defined terms have the meanings contained in the Trust Instrument.

Derivative Actions

The Second Amended and Restated Trust Instrument (the "Trust Instrument") requires, within Section 9 of Article IV, that before bringing any derivative action on behalf of the Fund, Shareholders must have made a written demand to the Board of Trustees requesting that they cause the Trust or affected Series or Class, as applicable, to file the action itself.

In order to warrant consideration, any such written demand must include at least the following:

(1) a detailed description of the action or failure to act complained of and the facts upon which each such allegation is made;

(2) a statement to the effect that the complaining Shareholders believe that they will fairly and adequately represent the interests of similarly situated Shareholders in enforcing the right of the Trust or the affected Series or Class, as applicable and an explanation of why the complaining Shareholders believe that to be the case;

(3) a certification that the following requirements have been met, as well as information reasonably designed to allow the Trustees to verify that certification:

(a) each complaining Shareholder was a Shareholder of the Trust or the affected Series or Class, as applicable, at the time of the action or failure to act complained of, or acquired the Shares afterwards by operation of law from a Person who was a Shareholder at that time; and

(b) each complaining Shareholder was a Shareholder of the Trust or the affected Series or Class, as applicable, as of the time the demand required by Section 9 of Article IV was made; and

(4) a certification that each complaining Shareholder will be a Shareholder of the Trust or the affected Series or Class, as applicable as of the commencement of the derivative action.

The Trust Instrument further provides that at least 10% of the Shareholders of the Trust or the affected Series or Class, as applicable, must join in bringing the derivative action. This provision does not apply to claims brought under the federal securities laws.

The Trust Instrument also provides that a copy of the derivative complaint must be served on the Trust, assuming the requirements described above have already been met and the derivative action has not been barred as further described in the Trust Instrument.

PROSPECTUS |

Other Information

Forum and Waiver of Jury Trial

Section 10 of Article X of the Trust Instrument outlines which shareholder actions must be brought in state court and which must be brought in federal court. This section states in particular that, unless the Trust consents in writing to the selection of an alternative forum, the Federal District Courts of the United States of America shall be the sole and exclusive forum for the resolution of any complaint asserting a cause of action arising under any federal securities law. This provision may increase costs for a shareholder to bring a claim or may limit a shareholder's ability to bring a claim in a judicial forum that they find more convenient or favorable. While the enforceability of the exclusive forum provisions may be challenged, this section also provides that if any provisions of Section 10 shall be held to be invalid, illegal or unenforceable, the validity, legality and enforceability of the remaining portions will still apply.

Section 10 of Article X of the Trust Instrument also states that shareholders and all other such persons bringing any such suit, action, or proceeding in the Superior Court in the State of Delaware waive the right to a trial by jury to the fullest extent permitted by law.

For more detailed information on the Fund, several additional sources of information are available to you. The Fund's SAI, incorporated by reference into this prospectus, contains detailed information on the Fund's policies and operation. Additional information about the Fund's investments is available in the annual and semi-annual reports to shareholders. In the Fund's annual reports, you will find a discussion of the market conditions and investment strategies that significantly impacted the Fund's performance during the last fiscal year. The Fund's most recent SAI, annual or semi-annual reports and certain other information are available free of charge by calling the Fund at (866) 363-9219, on the Fund's website at www.calamos.com or through your financial advisor. Shareholders may call the toll-free number above with any inquiries.

You may obtain this and other information regarding the Fund, including the SAI and Codes of Ethics adopted by the Adviser, Distributor and the Trust, directly from the SEC. Information on the SEC's website is free of charge. Visit the SEC's on-line EDGAR database at http://www.sec.gov. You may also request information regarding the Fund by sending a request (along with a duplication fee) to the SEC by sending an electronic request to [email protected].

Calamos Laddered S&P 500^® Structured Alt Protection ETF^TM

2020 Calamos Court
Naperville, IL 60563-2787
866.363.9219
www.calamos.com

SEC File
#811-22887

[TO COME]STAPRO [TO COME]24

The information in this Statement of Additional Information is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This Statement of Additional Information is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any state where the offer of sale is not permitted.

Subject to Completion

August 21, 2024

Dated September [TO COME], 2024

STATEMENT OF ADDITIONAL INFORMATION

Fund		Ticker
Calamos Laddered S&P 500 Structured Alt Protection ETF		[TO COME]

2020 Calamos Court
Naperville, Illinois 60563
866.363.9219

This Statement of Additional Information ("SAI") relates to Calamos Laddered S&P 500 Structured Alt Protection ETF (the "Fund"), a series of the Calamos ETF Trust (the "Trust"). This is not a prospectus, but provides information that should be read in conjunction with the prospectus for the Fund, dated September [TO COME], 2024 in and any supplements thereto, which are incorporated herein by reference. Capitalized terms used herein that are not defined have the same meanings as in the Prospectus, unless otherwise noted. A copy of the Prospectus may be obtained without charge by calling the Fund at (866) 363-9219, visiting the Fund's website at www.calamos.com or through your financial advisor.

References to the Investment Company Act of 1940, as amended (the "1940 Act"), or other applicable law, will include any rules promulgated thereunder and any guidance, interpretations or modifications by the Securities and Exchange Commission (the "SEC"), SEC staff or other authority with appropriate jurisdiction, including court interpretations, and exemptive, no action or other relief or permission from the SEC, SEC staff or other authority.

TABLE OF CONTENTS

		Page
THE TRUST AND THE FUND		1
EXCHANGE LISTING AND TRADING		1
DISCLOSURE OF PORTFOLIO HOLDINGS		2
INVESTMENT OBJECTIVE		2
INVESTMENT PRACTICES		2
INVESTMENT RESTRICTIONS		15
MANAGEMENT		16
CONTROL PERSONS AND PRINCIPAL HOLDERS OF SECURITIES		26
INVESTMENT ADVISORY SERVICES		26
DISTRIBUTOR		29
OTHER COMPENSATION TO INTERMEDIARIES		30
PORTFOLIO TRANSACTIONS		31
ADDITIONAL INFORMATION CONCERNING THE FUND SHARES		32
CREATION AND REDEMPTION OF CREATION UNITS		33
TAXATION		41
CUSTODIAN AND TRANSFER AGENT		49
FUND ACCOUNTING AND FINANCIAL ACCOUNTING AGENT		49
MISCELLANEOUS		50
FINANCIAL STATEMENTS		50

THE TRUST AND THE FUND

The Trust was organized as a Delaware statutory trust on June 17, 2013. The Trust is an open-end, registered management investment company. The Trust currently offers Fund Shares in twenty-five series of the Trust. Series other than the Funds are offered through separate prospectuses and statements of additional information and are not further discussed herein. The offering of the Fund's shares ("Fund Shares") is registered under the Securities Act of 1933, as amended (the "Securities Act").

The Fund is a non- diversified, actively managed exchange-traded fund. The Fund offers and issues Fund Shares at net asset value ("NAV") only in aggregations of a specified number of Fund Shares, generally in exchange for a basket of securities constituting the portfolio holdings of the Fund, together with the deposit of a specified cash payment, or, in certain circumstances, for an all-cash payment. Fund Shares will be listed and principally traded on Cboe BZX Exchange, Inc. (the "Exchange"). Fund Shares will trade on the Exchange at market prices that may be below, at, or above NAV.

Unlike mutual funds, Fund Shares are not individually redeemable securities. Rather, the Fund issues and redeems Fund Shares on a continuous basis at NAV, typically in creation units of 25,000 Fund Shares (each, a "Creation Unit") In the event of the liquidation of the Fund, the Trust may lower the number of Fund Shares in a Creation Unit. Financial entities known as "authorized participants" (which are discussed in greater detail below) have contractual arrangements with the Fund or the Distributor to purchase and redeem Fund Shares directly with the Fund in Creation Units in exchange for the securities comprising the Fund and/or cash, or some combination thereof. Fund Shares are traded in the secondary market and elsewhere at market prices that may be at, above, or below the Fund's NAV. Fund Shares are only redeemable in Creation Units by authorized participants. An authorized participant that purchases a Creation Unit of Fund Shares deposits with the Fund a "basket" of securities and/or other assets identified by the Fund that day, and then receives the Creation Unit of Fund Shares in return for those assets. The redemption process is the reverse of the purchase process: the authorized participant redeems a Creation Unit of Fund Shares for a basket of securities and other assets. The basket is generally representative of the Fund's portfolio, and together with a cash balancing amount, it is equal to the NAV of the Fund Shares comprising the Creation Unit. Pursuant to Rule 6c-11 of the 1940 Act ("Rule 6c-11"), the Fund may utilize baskets that are not representative of the Fund's portfolio. Such "custom baskets" are discussed in the section entitled "Creations and Redemptions of Creation Units." Transaction fees and other costs associated with creations or redemptions that include cash may be higher than the transaction fees and other costs associated with in-kind creations or redemptions. In all cases, conditions with respect to creations and redemptions of Fund Shares and fees will be limited in accordance with the requirements of SEC rules and regulations applicable to management investment companies offering redeemable securities.

The Board of Trustees of the Trust (the "Board of Trustees" or the "Trustees") has the right to establish additional series in the future, to determine the preferences, voting powers, rights and privileges thereof and to modify such preferences, voting powers, rights and privileges without shareholder approval. Fund Shares of any series may also be divided into one or more classes at the discretion of the Trustees. The Trust or any series or class thereof may be terminated at any time by the Board of Trustees upon written notice to the shareholders.

EXCHANGE LISTING AND TRADING

Fund Shares of the Fund are listed and traded on the Cboe BZX Exchange, Inc. Fund Shares trade on the Exchange or in secondary markets at prices that may differ from their NAV or Intraday Indicative Value ("IIV"), because such prices may be affected by market forces (such as supply and demand for Fund Shares). As is the case of other securities traded on an exchange, when you buy or sell Fund Shares on the Exchange or in the secondary markets your broker will normally charge you a commission or other transaction charges. Further, the Trust reserves the right to adjust the price of Fund Shares in the future to maintain convenient trading ranges for investors (namely, to maintain a price per Share that is attractive to investors) by share splits or reverse share splits, which would have no effect on the NAV.

There can be no assurance that the requirements of the Exchange necessary to maintain the listing of Fund Shares of the Fund will continue to be met.

The Fund is not sponsored, endorsed, sold or promoted by the Exchange. The Exchange makes no representation or warranty, express or implied, to the owners of Fund Shares of the Fund or any member of the public regarding the advisability of investing in securities generally or in the Fund particularly or the ability of the Fund to achieve its objectives. The Exchange has no obligation or liability in connection with the administration, marketing or trading of the Fund.

DISCLOSURE OF PORTFOLIO HOLDINGS

The Board has adopted a policy regarding the disclosure of information about the Fund's portfolio securities. Under the policy, portfolio holdings of the Fund, which will form the basis for the calculation of NAV on any day on which the Trust is open for business ("Business Day"), are publicly disseminated prior to the opening of trading on the Exchange that Business Day through financial reporting or news services, including the website www.calamos.com. In addition, each Business Day a portfolio composition file, which displays the basket of securities to be deposited to purchase Creation Units of the Fund ("In-Kind Creation Basket") and the amount of cash necessary to equal the difference between the NAV of a Creation Unit and the market value of the In-Kind Creation Basket ("Cash Component"), is publicly disseminated prior to the opening of the Exchange via the National Securities Clearing Corporation ("NSCC").

INVESTMENT OBJECTIVE

The Fund's investment objective is to seek to provide investors with capital appreciation.

The Fund seeks to achieve its investment objective by providing investors with US large-cap equity market exposure while attempting to limit downside risk through a laddered portfolio of twelve Calamos S&P 500® Structured Alt Protection ETFs (the "Underlying ETFs"). The term "laddered portfolio" refers to the Fund's investment in multiple Underlying ETFs that have target outcome period expiration dates which occur on a rolling, or periodic, basis.

The Fund's investment objective is non-fundamental and may be changed by a vote of the Fund's Board, without shareholder approval.

The Fund has adopted a non-fundamental operating policy that requires it, under normal circumstances, to invest at least 80% of its net assets (plus borrowings for investment purposes, if any) in ETFs. Although this requirement may be changed by the Board of Trustees without shareholder approval, the Fund will notify shareholders in writing at least 60 days prior to any change in its 80% policy.

INVESTMENT PRACTICES

The prospectus contains information concerning the Fund's investment objective and principal investment strategies and risks. This Statement of Additional Information provides additional information concerning certain securities and strategies used by the Fund and their associated risks. References to the Fund's investments also generally refer to the Underlying ETFs' investments.

In pursuing its investment objective, the Fund will invest as described below and in the Fund's prospectus. The table below indicates whether the Fund, directly or indirectly through its investment in the Underlying ETFs, invests in the securities and instruments listed as part of its principal (P) or non-principal (N) investment strategies.

Unless otherwise noted, all investment policies and restrictions described in the Prospectus and Statement of Additional Information are measured at the time of the transaction in the security. If market action affecting fund securities (including, but not limited to, appreciation, depreciation, or a credit rating event) causes the Fund to exceed an investment policy or restriction, Calamos Advisors LLC ("Calamos Advisors" or the "Adviser") is not required to take immediate action. Under normal market conditions, however, Calamos Advisors will not make any acquisitions that will make the Fund further outside the investment restriction.

INVESTMENTS AND INVESTMENT- RELATED PRACTICES		CALAMOS LADDERED S&P 500 STRUCTURED ALT PROTECTION ETF
Currency Exchange Transactions		P
Equity Securities		P
FLEX Options		P
Illiquid Securities		N
Initial Public Offerings		N
Master Limited Partnerships		N
Options on Securities, Indexes and Currencies		P
Other Investment Companies		P
Repurchase Agreements		N
Reverse Repurchase Agreements and Other Borrowings		N
Rule 144A Securities		N
Temporary Investments		N
U.S. Government Obligations		P
Warrants		N
"When-Issued" and Delayed Delivery Securities		N

CURRENCY EXCHANGE TRANSACTIONS

Currency exchange transactions may be conducted either on a spot (i.e., cash) basis at the spot rate for purchasing or selling currency prevailing in the foreign exchange market or through forward currency exchange contracts ("forward contracts"). Forward contracts are contractual agreements to purchase or sell a specified currency at a specified future date (or within a specified time period) and price set at the time of the contract.

Forward contracts are usually entered into with banks, foreign exchange dealers and broker-dealers, are not exchange traded, and are usually for less than one year, but may be renewed.

Forward currency exchange transactions may involve currencies of the different countries in which the Fund may invest and serve as hedges against possible variations in the exchange rate between these currencies. Currency exchange transactions are limited to transaction hedging and portfolio hedging involving either specific transactions or portfolio positions. Transaction hedging is the purchase or sale of forward contracts with respect to specific receivables or payables of the Fund accruing in connection with the purchase and sale of its portfolio securities or the receipt of dividends or interest thereon. Portfolio hedging is the use of forward contracts with respect to portfolio security positions denominated or quoted in a particular foreign currency. Portfolio hedging allows the Fund to limit or reduce its exposure in a foreign currency by entering into a forward contract to sell such foreign currency (or another foreign currency that acts as a proxy for that currency) at a future date for a price payable in U.S. dollars so that the value of the foreign denominated portfolio securities can be approximately matched by a foreign denominated liability. The Fund may not engage in portfolio hedging with respect to the currency of a particular country to an extent greater than the aggregate market value (at the time of making such sale) of the securities held in its portfolio denominated or quoted in that particular currency, except that the Fund may hedge all or part of its foreign currency exposure through the use of a basket of currencies or a proxy currency where such currencies or currency act as an effective proxy for other currencies. In such a case, the Fund may enter into a forward contract where the amount of the foreign currency to be sold exceeds the value of the securities denominated in such currency. The use of this basket hedging technique may be more efficient and economical than entering into separate forward contracts for each currency held in the Fund. The Fund may not engage in "speculative" currency exchange transactions.

At the maturity of the forward contract to deliver a particular currency, the Fund may either sell the portfolio security related to the contract and make delivery of the currency, or it may retain the security and either acquire the currency on the spot market or terminate its contractual obligation to deliver the currency by purchasing an offsetting contract with the same currency trader obligating it to purchase on the same maturity date the same amount of the currency.

It is impossible to forecast with absolute precision the market value of portfolio securities at the expiration of a forward contract. Accordingly, it may be necessary for the Fund to purchase additional currency on the spot market (and bear the expense of such purchase) if the market value of the security is less than the amount of currency the Fund is obligated to deliver and if a decision is made to sell the security and make delivery of the currency. Conversely, it may be necessary to sell on the spot market some of the currency received upon the sale of the portfolio security if its market value exceeds the amount of currency the Fund is obligated to deliver.

If the Fund retains the portfolio security and engages in an offsetting currency transaction, it will incur a gain or a loss to the extent that there has been movement in forward contract prices. If the Fund engages in an offsetting currency transaction, it subsequently may enter into a new forward contract to sell the currency. Should forward prices decline during the period between the Fund entering into a forward contract for the sale of a currency and the date it enters into an offsetting contract for the purchase of the currency, the Fund will realize a gain to the extent the price of the currency it has agreed to sell exceeds the price of the currency it has agreed to purchase. Should forward prices increase, the Fund will suffer a loss to the extent the price of the currency it has agreed to purchase exceeds the price of the currency it has agreed to sell. A default on the contract would deprive the Fund of unrealized profits or force the Fund to cover its commitments for purchase or sale of currency, if any, at the current market price.

Hedging against a decline in the value of a currency does not eliminate fluctuations in the value of a portfolio security traded in that currency or prevent a loss if the value of the security declines. Hedging transactions also preclude the opportunity for gain if the value of the hedged currency should rise.

Moreover, it may not be possible for the Fund to hedge against a devaluation that is so generally anticipated that the Fund is not able to contract to sell the currency at a price above the devaluation level it anticipates. The cost to the Fund of engaging in currency exchange transactions varies with such factors as the currency involved, the length of the contract period, and prevailing market conditions. Because currency exchange transactions are usually conducted on a principal basis, no fees or commissions are involved.

EQUITY SECURITIES

Equity securities include common and preferred stocks, warrants, rights, and depository receipts. An investment in the equity securities of a company represents a proportionate ownership interest in that company. Therefore, the Fund participates in the financial success or failure of any company in which it has an equity interest.

Equity investments are subject to greater fluctuations in market value than other asset classes as a result of such factors as the issuer's business performance, investor perceptions, stock market trends and general economic conditions. Equity securities are subordinated to bonds and other debt instruments in a company's capital structure in terms of priority to corporate income and liquidation payments. See the prospectus for additional information regarding equity investments and their risks.

FLEX OPTIONS

FLexible EXchange^® Options ("FLEX Options") are customized option contracts available through national securities exchanges that are guaranteed for settlement by the Options Clearing Corporation ("OCC"). FLEX Options are listed on a U.S. national securities exchange. FLEX Options provide investors with the ability to customize assets referenced by the options, exercise prices, exercise styles (i.e., American-style, exercisable any time prior to the expiration date, or European-style, exercisable only on the option expiration date) and expiration dates, while achieving price discovery in competitive, transparent auctions markets and avoiding the counterparty exposure of over-the-counter ("OTC") options positions. Each option contract entitles the holder thereof to purchase (for the call options) or sell (for the put options) shares of the reference asset at the strike price.

The OCC guarantees performance by each of the counterparties to the FLEX Options, becoming the "buyer for every seller and the seller for every buyer", with the goal of protecting clearing members and options traders from counterparty risk.

Certain Considerations Regarding Options. The FLEX Options in which each of the Underlying ETFs invest will be options on an index, the S&P 500 Index or an exchange-traded fund ("ETF") (each, a "Reference Asset"). As such, the value of the Underlying ETF's FLEX Options will fluctuate with changes in the value of the securities included in, or held by, the Reference Asset, and thus the Reference Asset's price return. In addition to the value of the Reference Asset, the value of an option contract, in general, will reflect, among other things, the time remaining until its expiration date, the relationship of the exercise price to the market price of the underlying investment, and general market conditions. Option contracts that expire unexercised have no value.

Each of the options exchanges has established limitations governing the maximum number of call or put options on the same asset that may be bought or written by a single investor, whether acting alone or in concert with others (regardless of whether such options are written on the same or different exchanges or are held or written on one or more accounts or through one or more brokers). Under these limitations, option positions of all investment companies advised by Calamos Advisors LLC ("Calamos Advisors" or the "Adviser") are combined for purposes of these limits. Pursuant to these limitations, an exchange may order the liquidation of positions and may impose other sanctions or restrictions.

These positions limits may restrict the number of listed options that each Underlying ETF may buy or sell. The puts and calls on the Reference Asset entitle the purchaser of the option the right to purchase (for a call option) or sell (for a put option) the Reference Asset at a predetermined specified price (the "strike price"). When each Underlying ETF writes a call on the Reference Asset, it receives a premium and agrees that the purchaser of the call, upon exercise of the call, will receive from each Underlying ETF the delivery of an amount of cash or a specified number of Fund Shares of the Reference Asset in exchange for the strike price. When each Underlying ETF buys a call on the Reference Asset, it pays a premium and has the same rights to such call as indicated above. When each Underlying ETF buys a put on the Reference Asset, it pays a premium and has the right to require the seller of the put, upon the Underlying ETF's exercise of the put, to deliver an amount of cash or a specified number of Fund Shares of the Reference Asset in exchange for the strike price. When each Underlying ETF writes a put on the Reference Asset, it receives a premium and the purchaser of the put has the right to require the Underlying ETF to deliver an amount of cash or a specified number of shares of the Reference Asset in exchange for the strike price. Notwithstanding the above, each Underlying ETF utilizes FLEX Options that are cash-settled. Cash-settled option contracts give the holder the right to receive an amount (or owe an amount) of cash upon the exercise of the option contract. Gain or loss depends on changes in the value of the Reference Asset's price return relative to the strike price for a given option contract. The amount of cash is equal to the difference between the closing price of the Reference Asset's price return and the exercise price of the option contract times a specified multiple ("multiplier"), which determines the total value for each point of such difference.

Risks of Options on the Reference Asset. If the Underlying ETF has purchased an option and exercises it before the closing value for that day is available, it runs the risk that the Reference Asset's price return may subsequently change. If such a change causes the exercised option to fall out of the money, the Underlying ETF will be required to pay the difference between the closing value of the Reference Asset's value and the exercise price of the option (times the applicable multiplier) to the assigned writer.

LIMITATIONS ON OPTIONS AND FUTURES

If options, futures contracts or futures options of types other than those described herein are traded in the future, the Fund may also use those investment vehicles, provided the Board of Trustees determines that their use is consistent with the Fund's investment objectives.

The Fund may not maintain open short positions in futures contracts, call options written on futures contracts or call options written on indexes if, in the aggregate, the market value of all such open positions exceeds the current value of the securities in its portfolio, plus or minus unrealized gains and losses on the open positions, adjusted for the historical relative volatility of the relationship between the portfolio and the positions. For this purpose, to the extent the Fund has written call options on specific securities in its portfolio, the value of those securities will be deducted from the current market value of the securities portfolio.

The use of options and futures is subject to applicable regulations of the Securities and Exchange Commission ("SEC"), the several exchanges upon which they are traded and the Commodity Futures Trading Commission ("CFTC"). For example, the CFTC and domestic futures exchanges have established (and continue to evaluate and monitor) speculative position limits ("position limits") on the maximum speculative position which any person, or group of persons acting in concert, may hold or control in particular contracts. In addition, federal position limits apply to swaps that are economically equivalent to futures contracts on certain agricultural, metals and energy commodities. All positions owned or controlled by the same person or entity, even if in different accounts, must be aggregated for purposes of complying with the speculative limits. Thus, even if the Fund does not intend to exceed applicable position limits, it is possible that different clients managed by the Adviser and its affiliates may be aggregated for this purpose. Therefore, the trading decisions of the Adviser may have to be modified and positions held by the Fund liquidated in order to avoid exceeding such limits. The modification of investment decisions or the elimination of open positions, if it occurs, may adversely affect the profitability of the Fund. A violation of position limits could also lead to regulatory action materially adverse to the Fund's investment strategy.

Calamos Advisors has claimed an exclusion from the definition of commodity pool operator ("CPO") with respect to the Fund pursuant to Rule 4.5 under the Commodity Exchange Act ("CEA"). Consequently, Calamos Advisors is not subject to registration or regulation as a commodity pool operator under the CEA.

Under Rule 4.5, if the Fund uses commodity interests (such as futures contracts, options on futures contracts and swaps) other than for bona fide hedging purposes (as defined by the CFTC) the aggregate initial margin and premiums required to establish these positions (after taking into account unrealized profits and unrealized losses on any such positions and excluding the amount by which options that are "in-the-money"¹ at the time of purchase) may not exceed 5% of the Fund's NAV, or alternatively, the aggregate net notional value of those positions, as determined at the time the most recent position was established, may not exceed 100% of the Fund's NAV (after taking into account unrealized profits and unrealized losses on any such positions). The Fund is subject to the risk that a change in U.S. law and related regulations will impact the way the Fund operates, increase the particular costs of the Fund's operation and/or change the competitive landscape. In this regard, any further amendments to the CEA or its related regulations that subject the Fund to additional regulation may have adverse impacts on the Fund's operations and expenses.

ILLIQUID SECURITIES

The Fund may invest up to 15% of its net assets under regulatory rules, taken at market value, in illiquid investments that are assets, including any securities that are not readily marketable either because they are restricted securities or for other reasons. Restricted securities are securities that are subject to restrictions on resale because they have not been registered for sale under the Securities Act of 1933, as amended ("Securities Act"). A position in restricted securities might adversely affect the liquidity and marketability of a portion of the Fund's portfolio, and the Fund might not be able to sell or dispose of its holdings in such securities promptly or at reasonable prices. In those instances where the Fund is required to have restricted securities held by it registered prior to sale by the Fund and the Fund does not have a contractual commitment from the issuer or seller to pay the costs of such registration, the gross proceeds from the sale of securities would be reduced by the registration costs and underwriting discounts. Any such registration costs are not included in the percentage limitation on the Fund's investment in restricted securities.

The liquidity of an investment will be determined based on relevant market, trading and investment specific considerations as set out in the Fund's liquidity risk management program (the "Liquidity Program") as required by Rule 22e-4 under the 1940 Act (the "Liquidity Rule"). Illiquid investments may trade at a discount to comparable, more liquid investments and the Fund may not be able to dispose of illiquid investments in a timely fashion or at their expected prices. If illiquid investments exceed 15% of the Fund's net assets, the Liquidity Rule and the Liquidity Program will require that certain remedial actions be taken.

INITIAL PUBLIC OFFERINGS

The Fund may purchase stock in an initial public offering ("IPO"). An IPO is a company's first offering of stock to the public, typically to raise additional capital. Fund Shares are given a market value reflecting expectations for the company's future growth. The market for these securities may be more volatile and entail greater risk of loss than investments in larger companies due to the absence of a prior public market, unseasoned trading, a limited number of Fund Shares available for trading, lack of information about the issuer and limited operating history.

The purchase of IPO shares may involve high transaction costs. Because of the price volatility of IPO shares, the Fund may choose to hold IPO shares for a very short period of time. This may increase the turnover of the Fund's portfolio and may lead to increased expenses to the Fund, such as commissions and transaction costs. Calamos Advisors cannot guarantee continued access to IPOs.

¹ A call option is "in-the-money" to the extent, if any, that the value of the futures contract that is the subject of the option exceeds the exercise price. A put option is "in-the-money" if the exercise price exceeds the value of the futures contract that is the subject of the option.

MASTER LIMITED PARTNERSHIPS

MLPs differ from investments in common stock as a result of limited control and limited rights to vote on matters affecting the MLP. MLP common units, like other equity securities, can be affected by macro-economic and other factors affecting the stock market in general, expectations of interest rates, investor sentiment towards an issuer or certain market sector, changes in a particular issuer's financial condition, or unfavorable or unanticipated poor performance of a particular issuer (in the case of MLPs, generally measured in terms of distributable cash flow). Prices of common units of individual MLPs, like the prices other equity securities, also can be affected by fundamentals unique to the partnership or company, including earnings power and coverage ratios. MLPs generally do not pay federal income tax at the partnership level. Rather, each Partner is allocated a share of the partnerships' income, gains, losses, deductions and credits. A change in current tax law, or a change in the underlying business of an MLP, could result in an MLP being treated as a corporation, instead of a partnership, for federal income tax purposes, which would result in such MLP being required to pay income tax on its taxable income. This would have the effect of reducing the amount of cash available for distribution by the MLP, potentially reducing the value of the Fund's investment and consequently your investment in the Fund. Although common units of MLPs trade on various exchanges, certain MLP securities trade less frequently than those of larger companies due to their smaller capitalization. As a result, the price of such MLPs may display abrupt and erratic movements at times. Additionally, it may be more difficult for the Fund to buy and sell significant amounts of such securities without unfavorable impact on prevailing market process. As a result, these securities may be difficult to dispose of at a fair price when Calamos Advisors desires to do so.

OPTIONS ON SECURITIES, INDEXES AND CURRENCIES

The Fund may purchase and sell (write) put options and call options on securities, indexes or foreign currencies. The Fund may purchase agreements, sometimes called cash puts, that may accompany the purchase of a new issue of bonds from a dealer.

A put option gives the purchaser of the option, upon payment of a premium, the right to sell, and the writer the obligation to buy, the underlying security, commodity, index, currency or other instrument at the exercise price. For instance, the Fund's purchase of a put option on a security might be designed to protect its holdings in the underlying instrument (or, in some cases, a similar instrument) against a substantial decline in the market value by giving such Fund the right to sell such instrument at the option exercise price. A call option, upon payment of a premium, gives the purchaser of the option the right to buy, and the seller the obligation to sell, the underlying instrument at the exercise price.

The Fund's purchase of a call option on a security, financial future, index, currency or other instrument might be intended to protect it against an increase in the price of the underlying instrument that it intends to purchase in the future by fixing the price at which it may purchase such instrument. The Fund may purchase and sell (write) exchange listed options and over-the-counter ("OTC") options. Exchange listed options are issued by a regulated intermediary such as the Options Clearing Corporation ("OCC"), which guarantees the performance of the obligations of the parties to such options. The discussion below uses the OCC as an example, but is also applicable to other financial intermediaries.

With certain exceptions, OCC issued and exchange listed options generally settle by physical delivery of the underlying security or currency, although in the future cash settlement may become available. Index options and Eurodollar instruments are cash settled for the net amount, if any, by which the option is "in-the-money" (i.e., where the value of the underlying instrument exceeds, in the case of a call option, or is less than, in the case of a put option, the exercise price of the option) at the time the option is exercised. Frequently, rather than taking or making delivery of the underlying instrument through the process of exercising the option, listed options are closed by entering into offsetting purchase or sale transactions that do not result in ownership of the new option.

OTC options are purchased from or sold to sellers or purchasers ("Option Counterparties") through direct bilateral agreement with such Option Counterparties. In contrast to exchange listed options, which generally have standardized terms and performance mechanics, all the terms of an OTC option, including such terms as method of settlement, term, exercise price, premium, guarantees and security, are set by negotiation of the parties. The Fund will only sell (write) OTC options (other than OTC currency options) that are subject to a buy-back provision permitting the Fund to require the Option Counterparty to sell the option back to the Fund at a formula price within seven days. The Fund generally is expected to enter into OTC options that have cash settlement provisions, although it is not required to do so. The staff of the SEC currently takes the position that OTC options purchased by the Fund, and portfolio securities "covering" the amount of the Fund's obligation pursuant to an OTC option sold by it (or the amount of assets equal to the formula price for the repurchase of the option, if any, less the amount by which the option is "in the money") are illiquid, and are subject to the Fund's limitation on investing no more than 15% of its net assets in illiquid securities.

The Fund may also purchase and sell (write) options on securities indexes and other financial indexes. Options on securities indexes and other financial indexes are similar to options on a security or other instrument except that, rather than settling by physical delivery of the underlying instrument, they settle by cash settlement, i.e., an option or an index gives the holder the right to receive, upon exercise of the option, an amount of cash if the closing level of the index upon which the option is based exceeds, in the case of a call, or is less than, in the case of a put, the exercise price of the option (except if, in the case of an OTC option, physical delivery is specified). This amount of cash is equal to the excess of the closing price of the index over the exercise price of the option, which also may be multiplied by a formula value. The seller of the option is obligated, in return for the premium received, to make delivery of this amount. The gain or loss on an option on an index depends on price movements in the instruments making up the market, market segment, industry or other composite on which the underlying index is based, rather than price movements in individual securities, as is the case with respect to options on securities.

The Fund will sell (write) call options and put options. A written option will be considered "covered" to the extent it has entered into an offsetting transaction or otherwise has segregated or earmarked cash or liquid assets equal to its uncovered obligations under the written option. For example, a call option written by the Fund could be covered by purchasing an offsetting call option, by purchasing or holding the underlying reference security or asset (or a security convertible into the underlying reference security or asset), or by segregating or earmarking cash or liquid assets equal to the exercise price of the written option (or such amount as is not otherwise covered by an offsetting transaction). The Fund writing a call option on an index would be considered as holding an offsetting position to the extent such Fund owned portfolio securities substantially correlating with the movement of the underlying reference index.

If an option written by the Fund expires, the Fund realizes a capital gain equal to the premium received at the time the option was written. If an option purchased by the Fund expires, the Fund realizes a capital loss equal to the premium paid.

The Fund will realize a capital gain from a closing purchase transaction if the cost of the closing option is less than the premium received from writing the option, or, if it is more, such Fund will realize a capital loss. If the premium received from a closing sale transaction is more than the premium paid to purchase the option, the Fund will realize a capital gain or, if it is less, the Fund will realize a capital loss. The principal factors affecting the market value of a put or a call option include supply and demand, interest rates, the current market price of the underlying security, asset or index in relation to the exercise price of the option, the volatility of the underlying security, asset or index, and the time remaining until the expiration date.

A put or call option purchased by the Fund is an asset of the Fund, valued initially at the premium paid for the option. The premium received for an option written by the Fund is recorded as a deferred credit. The value of an option purchased or written is marked-to-market daily and is valued at the closing price on the exchange on which it is traded or, if not traded on an exchange or no closing price is available, at the mean between the last bid and asked prices.

RISKS ASSOCIATED WITH OPTIONS

There are several risks associated with transactions in options. For example, there are significant differences between the securities markets, the currency markets and the options markets that could result in an imperfect correlation among these markets, causing a given transaction not to achieve Calamos Advisors' objective. A decision as to whether, when and how to use options involves the exercise of skill and judgment, and even a well-conceived transaction may be unsuccessful to some degree because of market behavior or unexpected events.

The Fund's ability to utilize options successfully will depend on Calamos Advisors' ability to predict pertinent market investments, which cannot be assured. The Fund's ability to close out its position as a purchaser or seller (writer) of an OCC or exchange listed put or call option is dependent, in part, upon the liquidity of the option market. Among the possible reasons for the absence of a liquid option market on an exchange are: (i) insufficient trading interest in certain options; (ii) restrictions on transactions imposed by an exchange; (iii) trading halts, suspensions or other restrictions imposed with respect to particular classes or series of options or underlying securities including reaching daily price limits; (iv) interruption of the normal operations of the OCC or an exchange; (v) inadequacy of the facilities of an exchange or OCC to handle current trading volume; or (vi) a decision by one or more exchanges to discontinue the trading of options (or a particular class or series of options), in which event the relevant market for that option on that exchange would cease to exist, although outstanding options on that exchange would generally continue to be exercisable in accordance with their terms. If the Fund was unable to close out an option that it has purchased on a security, it would have to exercise the option in order to realize any profit or the option would expire and become worthless. If the Fund was unable to close out a covered call option that it had written on a security, it would not be able to sell the underlying security until the option expired. As the writer of a covered call option on a security, the Fund foregoes, during the option's life, the opportunity to profit from increases in the market value of the security covering the call option above the sum of the premium and the exercise price of the call. As the writer of a covered call option on a foreign currency, the Fund foregoes, during the option's life, the opportunity to profit from any currency appreciation.

The hours of trading for listed options may not coincide with the hours during which the underlying financial instruments are traded. To the extent that the option markets close before the markets for the underlying financial instruments, significant price and rate movements can take place in the underlying markets that cannot be reflected in the option markets.

Unless the parties provide for it, there is no central clearing or guaranty function in an OTC option. As a result, if the Option Counterparty (as described above under "Options on Securities, Indexes and Currencies") fails to make or take delivery of the security, currency or other instrument underlying an OTC option it has entered into with the Fund or fails to make a cash settlement payment due in accordance with the terms of that option, the Fund will lose any premium it paid for the option as well as any anticipated benefit of the transaction. Accordingly, Calamos Advisors must assess the creditworthiness of each such Option Counterparty or any guarantor or credit enhancement of the Option Counterparty's credit to determine the likelihood that the terms of the OTC option will be satisfied.

The Fund may purchase and sell (write) call options on securities indexes and currencies. Even though the Fund will receive the option premium to help protect it against loss, a call sold by the Fund exposes such Fund during the term of the option to possible loss of opportunity to realize appreciation in the market price of the underlying security or instrument and may require the Fund to hold the security or instrument that it might otherwise have sold. In addition, a loss on a call option sold may be greater than the premium received. The Fund may purchase and sell (write) put options on securities indexes and currencies. In selling (writing) put options, there is a risk that the Fund may be required to buy the underlying index or currency at a disadvantageous price above the market price.

OTHER INVESTMENT COMPANIES

The Fund invests primarily in other ETFs. An ETF is a fund that holds a portfolio of securities and trades on a securities exchange and its shares may, at times, trade at a premium or discount to its net asset value. As a shareholder in a pooled investment vehicle, the Fund will bear its ratable share of that vehicle's expenses, and would remain subject to payment of that vehicle's management fees with respect to assets so invested. Shareholders would therefore be subject to duplicative expenses to the extent the Fund invests in other pooled asset vehicles. In addition, the Fund will also incur brokerage costs when purchasing and selling shares of ETFs.

Generally, investments in ETFs are subject to statutory limitations prescribed by the 1940 Act. These limitations include a prohibition on the Fund acquiring more than 3% of the voting shares of any other investment company, a prohibition on investing more than 5% of the Fund's total assets in the securities of any one investment company or more than 10% of its total assets, in the aggregate, in investment company securities.

The Fund will invest in the Underlying ETFs beyond these statutory limitations in reliance on Section 12(d)(1)(G) of the 1940 Act.

REPURCHASE AGREEMENTS

As part of its strategy for the temporary investment of cash, the Fund may enter into "repurchase agreements" pertaining to U.S. Government securities with member banks of the Federal Reserve System or primary dealers (as designated by the Federal Reserve Bank of New York) in such securities. The Fund may invest in repurchase agreements, provided that the Fund may not invest more than 15% of its net assets in illiquid securities, including repurchase agreements maturing in more than seven days, and any other illiquid securities. A repurchase agreement arises when the Fund purchases a security and simultaneously agrees to resell it to the vendor at an agreed upon future date. The resale price is greater than the purchase price, reflecting an agreed upon market rate of return that is effective for the period of time the Fund holds the security and that is not related to the coupon rate on the purchased security.

Such agreements generally have maturities of no more than seven days and could be used to permit the Fund to earn interest on assets awaiting long-term investment. The Fund requires continuous maintenance by the custodian for the Fund's account in the Federal Reserve/Treasury Book Entry System of collateral in an amount equal to, or in excess of, the market value of the securities that are the subject of a repurchase agreement. In the event of a bankruptcy or other default of a seller of a repurchase agreement, the Fund could experience both delays in liquidating the underlying security and losses, including: (a) possible decline in the value of the underlying security during the period while the Fund seeks to enforce its rights thereto; (b) possible subnormal levels of income and lack of access to income during this period; and (c) expenses of enforcing its rights. In an effort to reduce these risks, Calamos Advisors will monitor the creditworthiness of the firms with which the Fund enters into repurchase agreements.

REVERSE REPURCHASE AGREEMENTS AND OTHER BORROWINGS

The Fund may enter into reverse repurchase agreements, and economically similar transactions to the extent permitted under the leverage limitations of the 1940 Act and the Fund's investment restrictions described below. A reverse repurchase agreement is a repurchase agreement in which the Fund is the seller of, rather than the investor in, securities and agrees to repurchase them at an agreed-upon time and price. A reverse repurchase agreement enables the Fund to obtain cash to satisfy unusually heavy redemption requests or for other temporary or emergency purposes without needing to sell portfolio securities, or to earn additional income on portfolio securities, such as Treasury bills or notes. Use of a reverse repurchase agreement may be preferable to a regular sale and later repurchase of securities because it avoids certain market risks and transaction costs.

The Fund also may effect simultaneous purchase and sale transactions that are known as "sale-buybacks." A sale-buyback is similar to a reverse repurchase agreement, except that in a sale-buyback, the counterparty who purchases the security is entitled to receive any principal or interest payments made on the underlying security pending settlement of the Fund's repurchase of the underlying security.

RULE 144A SECURITIES

The Fund may purchase securities that have been privately placed but that are eligible for purchase and sale by certain qualified institutional buyers, such as the Fund, under Rule 144A ("Rule 144A Securities") under the Securities Act. Calamos Advisors, under the supervision and oversight of the Trust's Board of Trustees, will consider whether Rule 144A Securities are illiquid and thus subject to the Fund's restriction of investing no more than a specified percentage of its net assets in securities that are illiquid at the time of purchase. A determination of whether a Rule 144A Security is liquid or not is a question of fact. In making this determination, Calamos Advisors will consider the trading markets for the specific security, taking into account the unregistered nature of a Rule 144A Security. In addition, Calamos Advisors may consider the (1) frequency of trades and quotes for the security, as well as equivalent or underlying securities (e.g. the underlying common stock of a convertible security), (2) number of dealers and potential purchasers, (3) dealer undertakings to make a market and (4) nature of the security and of marketplace trades (e.g., the time needed to dispose of the security, the method of soliciting offers and the mechanics of transfer).

The liquidity of Rule 144A Securities will be monitored and, if as a result of changed conditions, it is determined that a Rule 144A Security is no longer liquid, the Fund's holdings of illiquid securities would be reviewed to determine what, if any, steps are required to assure that the Fund does not invest more than 15% of its net assets in illiquid securities. Investing in Rule 144A Securities could have the effect of increasing the amount of the Fund's assets invested in illiquid securities if qualified institutional buyers are unwilling to purchase such securities.

TEMPORARY INVESTMENTS

The Fund may make temporary investments without limitation when Calamos Advisors determines that a defensive position is warranted, or as a reserve for possible cash needs. Such investments may be in money market instruments, consisting of obligations of, or guaranteed as to principal and interest by, the U.S. Government or its agencies or instrumentalities; certificates of deposit, bankers' acceptances and other obligations of domestic banks having total assets of at least $500 million and that are regulated by the U.S. Government, its agencies or instrumentalities; commercial paper rated in the highest category by a recognized rating agency; cash; and repurchase agreements. See "Exhibit A - Description of Ratings" for a description of ratings of certain rating agencies and their significance.

U.S. GOVERNMENT OBLIGATIONS

U.S. Government Obligations include securities that are issued or guaranteed by the U.S. Treasury or by various U.S. Government agencies and instrumentalities. U.S. Treasury obligations ("U.S. Treasuries") include Treasury bills, Treasury notes, and Treasury bonds. U.S. Treasuries also include the separate principal and interest components of U.S. Treasuries that are traded under the Separate Trading of Registered Interest and Principal of Securities ("STRIPS") program. U.S. Treasury obligations are backed by the full faith and credit of the U.S. Obligations issued or guaranteed by U.S. Government agencies and instrumentalities may be supported by any of the following: (a) the full faith and credit of the U.S., (b) the right of the issuer to borrow an amount limited to a specific line of credit from the U.S. Treasury, (c) the discretionary authority of the U.S. Treasury to lend to such Government agency or instrumentality, or (d) the credit of the agency or instrumentality.

Government agencies that issue or guarantee securities backed by the full faith and credit of the U.S. include the Government National Mortgage Association ("GNMA") and the Small Business Administration. Government agencies and instrumentalities that issue or guarantee securities not backed by the full faith and credit of the U.S. include the Federal Farm Credit Banks, the Federal Home Loan Banks, the Federal Home Loan Mortgage Corporation ("FHLMC"), the Federal National Mortgage Association ("FNMA"), the Federal Land Bank, the Bank for Cooperatives, the Federal Intermediate Credit Bank, the Federal Financing Bank, the Resolution Funding Corporation, the Financing Corporation of America and the Tennessee Valley Authority. In the case of securities not backed by the full faith and credit of the U.S., the investor must look principally to the agency issuing or guaranteeing the obligation for ultimate repayment and may not be able to assert a claim against the U.S. in the event the agency or instrumentality does not meet its commitment.

In September 2008, the U.S. Treasury and the Federal Housing Finance Agency ("FHFA") announced that FNMA and FHLMC had been placed in conservatorship. The conservatorship is still in effect as of the date of this SAI and has no specified termination date. There can be no assurance as to when or how the conservatorship will be terminated or whether FNMA or FHLMC will continue to exist following the conservatorship or what their respective business structures will be during or following the conservatorship. Since that time, FNMA and FHLMC have received significant capital support through U.S. Treasury preferred stock purchases, as well as Treasury and Federal Reserve purchases of their mortgage-backed securities ("MBS"). The FHFA and the U.S. Treasury (through its agreement to purchase FNMA and FHLMC preferred stock) have imposed strict limits on the size of their mortgage portfolios. The FHFA, as conservator, has the power to repudiate any contract entered into by FNMA or FHLMC prior to its appointment if it determines that performance of the contract is burdensome and repudiation of the contract promotes the orderly administration of FNMA's or FHLMC's affairs. Further, the FHFA has the right to transfer or sell any asset or liability of FNMA or FHLMC without any approval, assignment or consent. If FHFA were to transfer any such guaranty obligation to another party, holders of FNMA or FHLMC MBS would have to rely on that party for satisfaction of the guaranty obligation and would be exposed to the credit risk of that party. No assurance can be given that the Federal Reserve or the U.S. Treasury will ensure that FNMA and FHLMC remain successful in meeting their obligations with respect to the debt and mortgage-backed securities that they issue.

In addition, the problems faced by FNMA and FHLMC, resulting in their being placed into federal conservatorship and receiving significant U.S. Government support, have sparked serious debate among federal policy makers regarding the continued role of the U.S. Government in providing liquidity for mortgage loans. In December 2011, Congress enacted the Temporary Payroll Tax Cut Continuation Act ("TCCA") of 2011 which, among other provisions, requires that FNMA and FHLMC increase their single-family guaranty fees by at least 10 basis points and remit this increase to Treasury with respect to all loans acquired by FNMA and FHLMC on or after April 1, 2012 and before January 1, 2022. Serious discussions among policymakers continue, however, as to whether FNMA and FHLMC should be nationalized, privatized, restructured, or eliminated altogether. FNMA reported in the second quarter of 2014 that there was "significant uncertainty regarding the future of our company, including how long the company will continue to exist in its current form, the extent of our role in the market, what form we will have, and what ownership interest, if any, our current common and preferred stockholders will hold in us after the conservatorship is terminated and whether we will continue to exist following conservatorship." FHLMC faces similar uncertainty about its future role. FNMA and FHLMC also are the subject of several continuing legal actions and investigations over certain accounting, disclosure or corporate governance matters, which (along with any resulting financial restatements) may continue to have an adverse effect on the guaranteeing entities.

The Fund may invest in securities issued or guaranteed by any of the entities listed above or by any other agency established or sponsored by the U.S. Government, provided that the securities are otherwise permissible investments of the Fund. Certain U.S. Government Obligations that have a variable rate of interest readjusted no less frequently than annually will be deemed to have a maturity equal to the period remaining until the next readjustment of the interest rate.

The Fund's yield will fluctuate due to changes in interest rates, economic conditions, quality ratings and other factors. The prepayment experience of the mortgages underlying mortgage-related securities, such as obligations issued by GNMA, may affect the value of, and return on, an investment in such securities.

WARRANTS

The Fund may invest in warrants. A warrant is a right to purchase common stock at a specific price (usually at a premium above the market value of the underlying common stock at time of issuance) during a specified period of time. A warrant may have a life ranging from less than a year to 20 years or longer, but a warrant becomes worthless unless it is exercised or sold before expiration. In addition, if the market price of the common stock does not exceed the warrant's exercise price during the life of the warrant, the warrant will expire worthless. Warrants have no voting rights, pay no dividends and have no rights with respect to the assets of the corporation issuing them. The percentage increase or decrease in the value of a warrant may be greater than the percentage increase or decrease in the value of the underlying common stock.

"WHEN-ISSUED" AND DELAYED DELIVERY SECURITIES

The Fund may purchase securities on a when-issued or delayed-delivery basis. Although the payment and interest terms of these securities are established at the time the Fund enters into the commitment, the securities may be delivered and paid for a month or more after the date of purchase, when their value may have changed. The Fund makes such commitments only with the intention of actually acquiring the securities, but may sell the securities before the settlement date if Calamos Advisors deems it advisable for investment reasons. The Fund may utilize spot and forward foreign currency exchange transactions to reduce the risk inherent in fluctuations in the exchange rate between one currency and another when securities are purchased or sold on a when-issued or delayed-delivery basis.

The use of this investment strategy, as well as entering into reverse repurchase agreements or engaging in other borrowing as described below, may increase net asset value fluctuation.

RECENT MARKET CONDITIONS

Since the 2008 financial crises, financial markets throughout the world have experienced periods of increased volatility, depressed valuations, decreased liquidity and heightened uncertainty and turmoil. Both domestic and international equity and fixed income markets experienced heightened volatility and turmoil, with issuers that have exposure to the real estate, mortgage and credit markets particularly affected.

In addition to the recent unprecedented turbulence in financial markets, the reduced liquidity in credit and fixed income markets may negatively affect many issuers worldwide. Reduced liquidity in these markets may mean there is less money available to purchase raw materials, goods and services, which may, in turn, bring down the prices of these economic staples. It may also result in some issuers having more difficulty obtaining financing and ultimately may lead to a decline in their stock prices. The values of some sovereign debt and of securities of issuers that hold that sovereign debt have fallen. These events, and the potential for continuing market turbulence, may have an adverse effect on the Fund. In addition, global economies and financial markets have become increasingly interconnected, which increases the possibilities that conditions in one country or region might adversely impact issuers in a different country or region.

The U.S. federal government and certain foreign central banks have acted to calm credit markets and increase confidence in the U.S. and world economies. Certain of these entities have injected liquidity into the markets and taken other steps in an effort to stabilize the markets and grow the economy. Certain foreign governments and central banks are implementing or discussing so-called negative interest rates (e.g., charging depositors who keep their cash at a bank) to spur economic growth. Further Federal Reserve or other U.S. or non-U.S. governmental or central bank actions, including interest rate increases or contrary actions by different governments, could negatively affect financial markets generally, increase market volatility and reduce the value and liquidity of securities in which the Funds invest.

The situation in the financial markets has led to increased regulation, and the need of many financial institutions for government help has given lawmakers and regulators new leverage. The Dodd-Frank Act initiated a dramatic revision of the U.S. financial regulatory framework that continues to unfold. The Dodd-Frank Act covers a broad range of topics, including (among many others) a reorganization of federal financial regulators; a process intended to improve financial systemic stability and the resolution of potentially insolvent financial firms; new rules for derivatives trading; the creation of the Consumer Financial Protection Bureau; the registration and additional regulation of hedge and private equity fund managers; and new federal requirements for residential mortgage loans. Instruments in which the Funds may invest, or the issuers of such instruments, may be affected by the legislation and regulations promulgated thereunder in ways that may be unforeseeable. Because these requirements are relatively new and evolving (and some of the rules are not yet final), their ultimate impact remains unclear.

The statutory provisions of the Dodd-Frank Act significantly change in several respects the ways in which investment products are marketed, sold, settled or terminated. For example, the Dodd-Frank Act mandates the elimination of references to credit ratings in numerous securities laws, including the 1940 Act. In addition, some types of swaps (including interest rate swaps and credit default index swaps on North American and European indices) are required to be centrally cleared. Clearinghouses and futures commission merchants have broad rights to increase margin requirements for existing cleared transactions or to terminate cleared transactions at any time. Any increase in margin requirements or termination by the clearing member or the clearinghouse may have an effect on the performance of the Fund.

Under rules adopted under the Dodd-Frank Act, certain cleared derivatives contracts are required to be executed through swap execution facilities ("SEFs"). A SEF is a trading platform where multiple market participants can execute derivatives by accepting bids and offers made by multiple other participants in the platform. Such requirements may make it more difficult and costly for investment funds, such as the Fund, to enter into highly tailored or customized transactions. Trading swaps on a SEF may offer certain advantages over traditional bilateral over-the-counter trading, such as ease of execution, price transparency, increased liquidity and/or favorable pricing. Execution through a SEF is not, however, without additional costs and risks, as parties are required to comply with SEF and rules and additional CFTC regulations, including disclosure and recordkeeping obligations, and SEF rights of inspection, among others. SEFs typically charge fees, and if the Fund executes derivatives on a swap execution facility through a broker intermediary, the intermediary may impose fees as well. The Fund also may be required to indemnify a SEF, or a broker intermediary who executes swaps on a SEF on the Fund's behalf, against any losses or costs that may be incurred as a result of the Fund's transactions on the SEF. In addition, the Fund may be subject to execution risk if it enters into a derivatives transaction that is required to be cleared, and no clearing member is willing to clear the transaction on the Fund's behalf. In that case, the transaction might have to be terminated, and the Fund could lose some or all of the benefit of any increase in the value of the transaction after the time of the trade.

The European Union, the United Kingdom and some other countries have implemented similar requirements to the Dodd-Frank Act requirements that will affect the Fund when it enters into derivatives transactions with a counterparty organized in those jurisdictions or otherwise subject to those jurisdictions' derivatives regulations.

New global requirements may also result in increased uncertainty about counterparty credit risk, and they may also limit the flexibility of the Fund to protect its interests in the event of an insolvency of a derivatives counterparty. In the event of a counterparty's (or its affiliate's) insolvency, the Fund's ability to exercise remedies, such as the termination of transactions, netting of obligations and realization on collateral, could be stayed or eliminated under new special resolution regimes adopted in the United States, the European Union, the United Kingdom and various other jurisdictions. Such regimes provide government authorities with broad authority to intervene when a financial institution is experiencing financial difficulty. In particular, with respect to counterparties who are subject to such proceedings in the European Union or the United Kingdom, the liabilities of such counterparties to the Fund could be reduced, eliminated, or converted to equity in such counterparties (sometimes referred to as a "bail in").

Additionally, U.S. regulators, the European Union, the United Kingdom and certain other jurisdictions have adopted minimum margin and capital requirements for uncleared derivatives transactions. These regulations may have a material impact on the Fund's use of uncleared derivatives. These rules impose minimum variation (and in some cases, initial) margin requirements on derivatives transactions between the Fund and its swap counterparties and may increase the amount of margin the Fund is required to provide. They impose regulatory requirements on the calculation of margin and the timing of transferring margin.

The CFTC and U.S. futures exchanges have established limits, referred to as "position limits," on the maximum net long or net short positions which any person, or group of persons acting in concert, may own or control in certain futures and options contracts. In addition, starting January 1, 2023, federal position limits apply to swaps that are economically equivalent to futures contracts that are subject to CFTC set speculative limits. All positions owned or controlled by the same person or entity, even if in different accounts, must be aggregated for purposes of determining whether the applicable position limits have been exceeded. Thus, even if the Fund does not intend to exceed applicable position limits, it is possible that different clients managed by the Adviser may be aggregated for this purpose. Therefore, the trading decisions of the Adviser may have to be modified and positions held by the Fund liquidated in order to avoid exceeding such limits. The modification of investment decisions or elimination of open positions that may be required to avoid exceeding such limits may adversely affect the performance of the Fund. A violation of position limits could also lead to regulatory action materially adverse to the Fund. The fund may also be affected by regimes of the European Union and United Kingdom that impose position limits on its trade of commodity derivative contracts.

In October 2020, the SEC adopted Rule 18f-4 under the 1940 Act, which applies to the Fund's use of derivative investments and certain financing transactions (e.g., reverse repurchase agreements). Among other things, Rule 18f-4 requires funds that invest in derivative instruments beyond a specified limited amount to apply a value-at-risk based limit to their use of certain derivative instruments and financing transactions and to adopt and implement a derivatives risk management program. A Fund that uses derivative instruments (beyond certain currency and interest rate hedging transactions) in a limited amount is not subject to the full requirements of Rule 18f-4. In connection with compliance with Rule 18f-4, funds are no longer required to comply with the asset segregation framework arising from prior SEC guidance for covering certain derivative instruments and related transactions.

These and other new rules and regulations could, among other things, further restrict the Fund's ability to engage in, or increase the cost to the Fund of, derivatives transactions, for example, by making some types of derivatives no longer available to the Fund or otherwise limiting liquidity. This may result in changes to the Fund's principal investment strategies and could adversely affect the Fund's performance and its ability to achieve its investment objective.

Economies and financial markets throughout the world are increasingly interconnected. Economic, financial or political events, trading and tariff arrangements, terrorism, natural disasters and other circumstances in one country or region could have profound impacts on global economies or markets. Widespread disease and virus epidemics, such as the recent coronavirus outbreak, could likewise be highly disruptive, adversely affecting individual companies, sectors, industries, markets, currencies, interest and inflation rates, credit ratings, investor sentiment, and other factors affecting the value of the Funds' investments. As a result, whether or not the Funds invest in securities of issuers located in or with significant exposure to the countries directly affected, the value and liquidity of the Funds' investments may be negatively affected.

European financial markets are vulnerable to volatility and losses arising from concerns about the potential exit of member countries from the European Union and/or the Eurozone and, in the latter case, the reversion of those countries to their national currencies. Defaults by Economic Monetary Union member countries on sovereign debt, as well as any future discussions about exits from the Eurozone, may negatively affect the Fund's investments in the defaulting or exiting country, in issuers, both private and governmental, with direct exposure to that country, and in European issuers generally. In addition, the United Kingdom left the European Union on January 31, 2020 (commonly referred to as "Brexit"). During an 11-month transition period, ending December 31, 2020, the United Kingdom and the European Union agreed to a Trade and Cooperation Agreement which sets out the agreement for certain parts of the future relationship between the European Union and the United Kingdom from 1 January 2021. The Trade and Cooperation Agreement does not provide the United Kingdom with the same level of rights or access to all goods and services in the European Union as the United Kingdom previously maintained as a member of the European Union and during the transition period. In particular the Trade and Cooperation Agreement does not include an agreement on financial services. Accordingly, uncertainty remains in certain areas as to the future relationship between the United Kingdom and the European Union. The uncertainty caused by the United Kingdom's departure from the European Union could lead to prolonged political, legal, regulatory, tax and economic uncertainty and wider instability and volatility in the financial markets of the United Kingdom and more broadly across Europe. It may also lead to weakening corporate and financial confidence in such markets as the United Kingdom renegotiates the regulation of the provision of financial services within and to persons in the European Union. Brexit could lead to market dislocation, heightened counterparty risk, an adverse effect on the management of market risk and, in particular, asset and liability management due in part to redenomination of financial assets and liabilities, an adverse effect on the management, operation and investment in the Fund and increased legal, regulatory or compliance burden for the Fund which may have a negative impact on the operations, financial condition, returns or prospects of the Fund. The consequences of the United Kingdom's, or another country's potential, exit from the European Union and/or Eurozone could also threaten the stability of the euro for remaining countries and could negatively affect the financial markets of other countries in the European Union and beyond.

TAX RISK

The Fund and each Underlying ETF intend to elect and to qualify each year to be treated as a "regulated investment company" ("RIC") as defined by Subchapter M of the Internal Revenue Code of 1986, as amended (the "Code"). To qualify and maintain its status as a RIC, the Fund and each Underlying ETF Fund must meet certain income, diversification and distributions tests. For purposes of the diversification test, the identification of the issuer (or, in some cases, issuers) of a particular investment can depend on the terms and conditions of that investment. In particular, there is no published Internal Revenue Service guidance or case law on how to determine the "issuer" of certain derivatives that each Underlying ETF will enter into. Based upon the language in the legislative history, each Underlying ETF intends to treat the issuer of an equity option as the referenced asset and to treat any income it may derive from an equity option as "qualifying income" under the provisions of the Code applicable to RICs. In the case of FLEX Options, assuming the referenced asset qualifies as a RIC, treating the issuer as the referenced asset would allow each Underlying ETF to count the FLEX Options as automatically diversified investments under the RIC diversification requirements. If the income is not qualifying income or the issuer of equity options, including FLEX Options, is not appropriately the referenced asset, an Underlying ETF may not qualify, or may be disqualified, as a RIC.

There is a risk that if the offsetting FLEX Options are held by a single person, the IRS may take the position that the FLEX Options, viewed together, should be treated as a single debt instrument for federal tax purposes. The result of such a position would be that an Underlying ETF would fail the RIC diversification test. Each Underlying ETF has obtained an opinion of tax counsel that the FLEX Options should not be collapsed into a single instrument. However, such an opinion is not binding upon the IRS or the courts.

If an Underlying ETF were to lose its status as a RIC for purposes of the Code, the Fund may fail its requirement to have a diversified portfolio and thus lose its own RIC status. If the Fund did not qualify as a RIC for any taxable year and certain relief provisions were not available, the Fund's taxable income would be subject to tax at the Fund level and to a further tax at the shareholder level when such income is distributed. In such event, in order to requalify for taxation as a RIC, the Fund might be required to recognize unrealized gains, pay substantial taxes and interest and make certain distributions. This would cause investors to incur higher tax liabilities than they otherwise would have incurred and would have a negative impact on Fund returns. In such event, the Fund's Board of Trustees may determine to reorganize or close the Fund or materially change the Fund's investment objective and strategies. In the event that the Fund fails to qualify as a RIC, the Fund will promptly notify shareholders of the implications of that failure.

INVESTMENT RESTRICTIONS

The Fund is classified as a non-diversified, open-end management investment company. Except as noted below, the Fund operates under the following investment restrictions and may not:

(i) act as an underwriter of securities, except insofar as it may be deemed an underwriter for purposes of the Securities Act on disposition of securities acquired subject to legal or contractual restrictions on resale;

(ii) purchase or sell real estate (although it may purchase securities secured by real estate or interests therein, or securities issued by companies that invest in real estate or interests therein), commodities or commodity contracts, except that the Fund may enter into (a) futures, options and options on futures, (b) forward contracts and (c) other financial transactions not requiring the delivery of physical commodities;

(iii) make loans, but this restriction shall not prevent the Fund from (a) investing in debt obligations, (b) investing in repurchase agreements or (c) lending portfolio securities, provided, however, that it may not lend securities if, as a result, the aggregate value of all securities loaned would exceed 33% of its total assets (taken at market value at the time of such loan);

(iv) borrow, except from banks, other affiliated funds and other entities to the extent permitted under the 1940 Act;^2,3,4

(v) invest in a security if more than 25% of the Fund's total assets (taken at market value at the time of a particular purchase) would be invested in the securities of issuers in any particular industry or group of industries, except to the extent that the Underlying ETF invests more than 25% of its assets in an industry or group of industries. This restriction does not apply to securities issued or guaranteed by the U.S. Government, its agencies or instrumentalities, or securities of other investment companies.

(vi) issue any senior security, except to the extent permitted under the 1940 Act;⁵

The above restrictions are fundamental policies and may not be changed with respect to the Fund without the approval of a "majority" of the outstanding shares of the Fund, which for this purpose means the approval of the lesser of (a) more than 50% of the outstanding voting securities of the Fund or (b) 67% or more of the outstanding shares if the holders of more than 50% of the outstanding shares of the Fund are present or represented at the meeting by proxy.

²The Fund does not intend to purchase securities when its borrowings exceed 5% of total assets.

³ The Fund's borrowing practices are limited by the 1940 Act. Currently, under the 1940 Act, the Fund may borrow in an aggregate amount not exceeding 33 1/3% of its total assets, including the proceeds of borrowings, for any purpose, but borrowings from entities other than banks may not exceed 5% of its total assets and may be only as a temporary measure for extraordinary or emergency purposes, unless the Fund has received an exemptive order from the SEC permitting it to borrow from other affiliated funds in excess of 5% of its total assets.

⁴ Certain trading practices and investments, such as reverse repurchase agreements, may be considered to be borrowings or involve leverage and thus are subject to the Investment Company Act restrictions. In accordance with Rule 18f-4 under the Investment Company Act, when the Fund engages in reverse repurchase agreements and similar financing transactions, the Fund may either (i) maintain asset coverage of at least 300% with respect to such transactions and any other borrowings in the aggregate, or (ii) treat such transactions as "derivatives transactions" and comply with Rule 18f-4 with respect to such transactions. Short-term credits necessary for the settlement of securities transactions and arrangements with respect to securities lending will not be considered to be borrowings under the policy. Practices and investments that may involve leverage but are not considered to be borrowings are not subject to the policy.

⁵ Currently, under the 1940 Act, a "senior security" does not include any promissory note or evidence of indebtedness where the indebtedness is for temporary purposes only and in an amount not exceeding 5% of the value of the total assets of the issuer at the time the loan is made. A loan is presumed to be for temporary purposes if it is repaid within 60 days and is not extended or renewed.

In addition to the fundamental restrictions listed above, the Fund has adopted the following as non-fundamental policies:

(a) The Fund intends to rely on Section 12(d)(1)(G) of the 1940 Act to invest in ETFs in excess of the limits imposed under the 1940 Act on investments in other investment companies;⁶

(b) The Fund may not invest in companies for the purpose of exercising control or management;

(c) The Fund may not purchase securities on margin (except for use of such short-term credits as are necessary for the clearance of transactions, including transactions in options, futures and options on futures), or participate on a joint or a joint and several basis in any trading account in securities, except in connection with transactions in options, futures and options on futures;

(d) The Fund may not make short sales of securities, except that the Fund may make short sales of securities (i) if the Fund owns an equal amount of such securities, or owns securities that are convertible or exchangeable, without payment of further consideration, into an equal amount of such securities, (ii) other than those described in clause (i), provided that no more than 20% of its net assets would be deposited with brokers as collateral or allocated to segregated accounts in connection with all outstanding short sales other than those described in clause (i);

(e) The Fund will invest no more than 15% of its net assets in illiquid securities. Illiquid securities mean any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment.

The non-fundamental investment restrictions above may be changed by the Board of Trustees without shareholder approval. Notwithstanding the foregoing investment restrictions, the Fund may purchase securities pursuant to the exercise of subscription rights. Far Eastern and European corporations frequently issue additional capital stock by means of subscription rights offerings to existing shareholders at a price substantially below the market price of the shares. The failure to exercise such rights would result in the Fund's interest in the issuing company being diluted. The market for such rights is not well developed in all cases and, accordingly, the Fund may not always realize full value on the sale of rights. The exception applies in cases where the limits set forth in the investment restrictions would otherwise be exceeded by exercising rights or would have already been exceeded as a result of fluctuations in the market value of the Fund's portfolio securities with the result that the Fund would be forced either to sell securities at a time when it might not otherwise have done so, to forego exercising the rights.

MANAGEMENT

TRUSTEES AND OFFICERS

The management of the Trust, including general supervision of the duties performed for the Funds under the investment management agreement between the Trust and Calamos Advisors, is the responsibility of its Board of Trustees. Each trustee elected will hold office for the lifetime of the Trust or until such trustee's earlier resignation, death or removal; however, each trustee who is not an interested person of the Trust shall retire as a trustee at the end of the calendar year in which the trustee attains the age of 75 years.

⁶ Under Section 12(d)(1)(A) of the 1940 Act, a Fund generally must limit its investment in other investment companies so that, as determined immediately after a Fund invests in another investment company: (i) not more than 3% of the outstanding voting shares of any one investment company will be owned by a Fund; (ii) not more than 5% of the value of its total assets will be invested in the securities of any one investment company; and (iii) not more than 10% of the value of its total assets will be invested in the aggregate in securities of investment companies as a group, except as permitted under the 1940 Act, the rules thereunder or SEC exemptive relief. Currently, under the 1940 Act, the rules thereunder and SEC exemptive relief, a Fund may invest in other investment companies in excess of the above limitations if certain requirements are met, including (i) that a Fund complies with Rule 12d1-4 under the 1940 Act or (ii) that any Fund whose shares are acquired by another Fund in accordance with Section 12(d)(1)(G) of the 1940 Act shall not purchase securities of a registered open-end investment company or registered unit investment trust in reliance on either Section 12(d)(1) (F) or Section 12(d)(1)(G) of the 1940 Act. A Fund may also invest without limitation in money market funds, provided a Fund complies with Rule 12d1-1 under the 1940 Act. These limitations do not apply in connection with a merger, consolidation, reorganization or acquisition of substantially all the assets of another investment company.

The following table sets forth each trustee's name, year of birth, position(s) with the Trust, number of portfolios in the Calamos Fund Complex overseen, principal occupation(s) during the past five years and other directorships held, and date first elected or appointed. Each trustee oversees each series of the Trust, including the Fund.

TRUSTEES WHO ARE INTERESTED PERSONS OF THE TRUST:

NAME AND YEAR OF BIRTH		POSITION(S) AND LENGTH OF TIME WITH THE TRUST		PORTFOLIOS IN FUND COMPLEX OVERSEEN		PRINCIPAL OCCUPATION(S) DURING THE PAST 5 YEARS AND OTHER DIRECTORSHIPS		EXPERIENCE, QUALIFICATIONS, ATTRIBUTES, SKILLS FOR BOARD MEMBERSHIP
John P. Calamos, Sr. (1940)*		Chairman, Trustee and President (since 2014)		58		Founder, Chairman and Global Chief Investment Officer, Calamos Asset Management, Inc. ("CAM"), Calamos Investments LLC ("CILLC"), Calamos Advisors LLC and its predecessor ("Calamos Advisors") and Calamos Wealth Management LLC ("CWM"); Global Chief Investment Officer, Calamos Antetokounmpo Asset Management LLC, doing business as CGAM ("CGAM"); Director, CAM; and previously Chief Executive Officer, Calamos Financial Services LLC and its predecessor ("CFS"), CAM, CILLC, Calamos Advisors, and CWM		Served for multiple years as a trustee of the Trust; more than 25 years of experience in the financial services industry; experience serving on boards of other entities, including other investment companies; and earned a Masters of Business Administration degree

TRUSTEES WHO ARE NOT INTERESTED PERSONS OF THE TRUST:

NAME AND YEAR OF BIRTH		POSITION(S) AND LENGTH OF TIME WITH THE TRUST		PORTFOLIOS IN FUND COMPLEX^ OVERSEEN		PRINCIPAL OCCUPATION(S) DURING THE PAST 5 YEARS AND OTHER DIRECTORSHIPS		EXPERIENCE, QUALIFICATIONS, ATTRIBUTES, SKILLS FOR BOARD MEMBERSHIP
John E. Neal (1950)		Trustee (since 2014); Lead Independent Trustee (since 2019)		59	^^	Retired; private investor; Director, Creation Investments (private international microfinance company); Director, Equity Residential Trust (publicly-owned REIT); Director, Centrust Bank (Northbrook, Illinois community bank); formerly, Director, Neuro-ID (private company providing prescriptive analytics for the risk industry) (until 2021); formerly, Partner, Linden LLC (health care private equity) (until 2018)		Served for multiple years as a trustee of the Trust; more than 25 years of experience in the financial services industry; experience serving on boards of other entities, including other investment companies; and earned a Masters of Business Administration degree
William R. Rybak (1951)		Trustee (since 2014)		58		Private investor; Chairman (since 2016) and Director (since 2010), Christian Brothers Investment Services Inc.; Trustee, JNL Series Trust and JNL Investors Series Trust (since 2007), JNL Variable Fund LLC (2007-2020), Jackson Variable Series Trust (2018-2020) and JNL Strategic Income Fund LLC (2007-2018), (open-end mutual funds)**; Trustee, Lewis University (since 2012); formerly Director, Private Bancorp (2003-2017); Executive Vice President and Chief Financial Officer, Van Kampen Investments, Inc. and subsidiaries (investment manager) (until 2000)		Served for multiple years as a trustee of the Trust; more than 25 years of experience in the financial services industry; experience serving on boards of other entities, including other investment companies; and earned a Masters of Business Administration degree

NAME AND YEAR OF BIRTH		POSITION(S) AND LENGTH OF TIME WITH THE TRUST		PORTFOLIOS IN FUND COMPLEX^ OVERSEEN		PRINCIPAL OCCUPATION(S) DURING THE PAST 5 YEARS AND OTHER DIRECTORSHIPS		EXPERIENCE, QUALIFICATIONS, ATTRIBUTES, SKILLS FOR BOARD MEMBERSHIP
Virginia G. Breen (1964)		Trustee (since 2015)		58		Private Investor; Trustee, UBS NY Fund Cluster (open-end funds) (since 2023)***; Director, Paylocity Holding Corporation (since 2018); Trustee, Neuberger Berman Private Equity Registered Funds (registered private equity funds) (since 2015)****; Director, UBS A&Q Fund Complex (closed-end funds) (since 2008)*****; Trustee, Jones Lang LaSalle Income Property Trust, Inc. (REIT) (2004-2023); Director, Tech and Energy Transition Corporation (blank check company) (2021-2023))		Served for multiple years as a trustee of the Trust; more than 25 years of experience in the financial services industry; experience serving on boards of other entities, including other investment companies; and earned a Masters of Business Administration degree
Lloyd A. Wennlund (1957)		Trustee (since 2022)		58		Trustee and Chairman, Datum One Series Trust (since 2020); Expert Affiliate, Bates Group, LLC (financial services consulting and expert testimony firm) (since 2018); Executive Vice President, The Northern Trust Company (1989-2017); President and Business Unit Head of Northern Funds and Northern Institutional Funds (1994-2017); Director, Northern Trust Investments (1998-2017); Governor (2004-2017) and Executive Committee member (2011-2017), Investment Company Institute Board of Governors; Member, Securities Industry Financial Markets Association (SIFMA) Advisory Council, Private Client Services Committee and Private Client Steering Group (2006-2017); Board Member, Chicago Advisory Board of the Salvation Army (2011-2019)		More than 25 years of experience in the financial services industry; experience serving on boards of other entities, including other investment companies

NAME AND YEAR OF BIRTH		POSITION(S) AND LENGTH OF TIME WITH THE TRUST		PORTFOLIOS IN FUND COMPLEX^ OVERSEEN		PRINCIPAL OCCUPATION(S) DURING THE PAST 5 YEARS AND OTHER DIRECTORSHIPS		EXPERIENCE, QUALIFICATIONS, ATTRIBUTES, SKILLS FOR BOARD MEMBERSHIP
Karen L. Stuckey (1953)		Trustee (since 2022)		58		Member (2015-2021) of Desert Mountain Community Foundation Advisory Board (non-profit organization); Partner (1990-2012) of PricewaterhouseCoopers LLP (professional services firm) (held various positions 1975-1990); Member of Executive, Nominating, and Audit Committees and Chair of Finance Committee (1992-2006); Emeritus Trustee (since 2007) of Lehigh University; member, Women's Investment Management Forum (professional organization) (since inception); formerly, Trustee, Denver Board of Oppenheimer Funds (open-end mutual funds) (2012-2019)		More than 25 years of experience in the financial services industry; experience serving on boards of other entities, including other investment companies
Christopher M. Toub (1959)		Trustee (since 2022)		58		Private investor; formerly Director of Equities, AllianceBernstein LP (until 2012)		More than 25 years of experience in the financial services industry; and earned a Masters of Business Administration degree

^ The Fund Complex consists of Calamos Investment Trust, Calamos Advisors Trust, Calamos Convertible Opportunities and Income Fund, Calamos Convertible and High Income Fund, Calamos Strategic Total Return Fund, Calamos Global Total Return Fund, Calamos Global Dynamic Income Fund, Calamos Dynamic Convertible and Income Fund, Calamos Long/Short Equity & Dynamic Income Trust, Calamos ETF Trust, Calamos Antetokounmpo Sustainable Equities Trust and Calamos Aksia Alternative Credit and Income Fund.

^^ Mr. Neal is the only Trustee of the Trust who oversees Calamos Aksia Alternative Credit and Income Fund.

* Mr. Calamos, Sr. is an "interested person" of the Trust as defined in the 1940 Act because he is an officer of the Trust and an affiliate of Calamos Advisors and CFS.

** Overseeing 131 portfolios in fund complex.

*** Overseeing thirty-eight portfolios in fund complex.

**** Overseeing twenty-one portfolios in fund complex.

***** Overseeing three portfolios in fund complex.

The address of each trustee is 2020 Calamos Court, Naperville, Illinois 60563.

OFFICERS. The preceding table gives information about John P. Calamos, Sr., who is Chairman, Trustee, and President of the Trust. The following table sets forth each other officer's name, year of birth, position with the Trust and date first appointed to that position, and principal occupation(s) during the past five years. Each officer serves until his or her successor is chosen and qualified or until his or her resignation or removal by the Board of Trustees.

NAME AND YEAR OF BIRTH		POSITION(S) WITH TRUST		PRINCIPAL OCCUPATION(S)
Robert Behan (1964)		Vice President (since 2014)		Executive Vice President, Chief Distribution Officer (since February 2021), CAM, CILLC, Calamos Advisors, and CFS; Vice President, CGAM (since 2022); prior thereto President (2015-February 2021), Head of Global Distribution (2013-February 2021); Executive Vice President (2013-2015); Senior Vice President (2009-2013), Head of US Intermediary Distribution (2010-2013)

Thomas E. Herman (1961)		Vice President (since 2016) and Chief Financial Officer (2016-2017 and since 2019)		Executive Vice President (since February 2021) and Chief Financial Officer, CAM, CILLC, Calamos Advisors, and CWM (since 2016); Chief Financial Officer and Treasurer, CGAM (since 2022); prior thereto, Chief Financial Officer and Treasurer, Harris Associates (2010-2016)
Erik D. Ojala (1975)		Vice President and Secretary (since 2023)		Senior Vice President, General Counsel and Secretary, CAM, CILLC, Calamos Advisors, CWM (since 2023); Chief Legal Officer, CGAM (since 2023); General Counsel and Secretary, CFS (since 2023); prior thereto, Executive Vice President and General Counsel (2017-2023), Secretary (2010-2023) and Chief Compliance Officer (2021-2023), Harbor Capital Advisors, Inc.; Director and Secretary (2019-2023) and Chief Compliance Officer (2022-2023), Harbor Trust Company, Inc.; Director, Executive Vice President (2017-2023) and Chief Compliance Officer (2017-2021, 2022-2023), Harbor Funds Distributors, Inc.; Director (2017-2023), Assistant Secretary (2014-2023) and Chief Compliance Officer (2022-2023), Harbor Services Group, Inc.; Chief Compliance Officer, Harbor ETF Trust (2021-2023); and Chief Compliance Officer of Harbor Funds (2017-2023).
John S. Koudounis (1966)		Vice President (since 2016)		President (since February 2021) and Chief Executive Officer, CAM, CILLC, Calamos Advisors, CWM, and CFS (since 2016); Chairman and Chief Executive Officer, CGAM (since 2022); Director, CAM (since 2016); prior thereto President and Chief Executive Officer (2010-2016), Mizuho Securities USA Inc.
Daniel Dufresne (1974)		Vice President (since 2022)		Executive Vice President and Chief Operating Officer, CAM, CILLC, Calamos Advisors, and CWM (since April 2021); President, CGAM (since 2022); prior thereto Citadel (1999-2020); Partner (2008-2020); Managing Director, Global Treasurer (2008-2020); Global Head of Operations (2011-2020); Global Head of Counterparty Strategy (2018-2020); Senior Advisor to the COO (2020); CEO, Citadel Clearing LLC (2015-2020).
Mark J. Mickey (1951)		Chief Compliance Officer (since 2014)		Chief Compliance Officer, Calamos Funds (since 2005)
Stephen Atkins (1965)		Treasurer (since 2022)		Senior Vice President, Head of Fund Administration (since February 2020), Calamos Advisors; prior thereto Consultant, Fund Accounting and Administration, Vx Capital Partners (March 2019-February 2020); Chief Financial Officer and Treasurer of SEC Registered Funds, and Senior Vice President, Head of European Special Purpose Vehicles Accounting and Administration, Avenue Capital Group (2010-2018)

The address of each officer is 2020 Calamos Court, Naperville, Illinois 60563.

COMMITTEES OF THE BOARD OF TRUSTEES. The Trust's Board of Trustees has established five standing committees: the Executive Committee, the Dividend Committee, the Audit Committee, the Valuation Committee and the Governance Committee.

Executive Committee. Messrs. John Calamos and John E. Neal are members of the executive committee, which has authority during intervals between meetings of the Board of Trustees to exercise the powers of the board, with certain exceptions. John Calamos is an interested trustee of the Trust.

Dividend Committee. Mr. John Calamos serves as the sole member of the dividend committee. The dividend committee is authorized, subject to Board review, to declare distributions on the Fund Shares of the Trust's series in accordance with such series' distribution policies, including, but not limited to, regular dividends, special dividends and short- and long-term capital gains distributions.

Audit Committee. Messrs. Neal, Rybak (Chair), Toub and Wennlund and Mses. Breen and Stuckey serve on the audit committee. The audit committee operates under a written charter adopted and approved by the board. The audit committee selects independent auditors, approves services to be rendered by the auditors, monitors the auditors' performance, reviews the results of the Trust's audit and responds to other matters deemed appropriate by the board. All members of the audit committee are independent trustees of the Trust.

Valuation Committee. Messrs. Neal, Rybak, Toub, and Wennlund (Chair) and Mses. Breen and Stuckey serve on the valuation committee. The valuation committee operates under a written charter approved by the board. The valuation committee oversees valuation matters of the Trust delegated to the valuation designee, including the fair valuation determinations and methodologies proposed and utilized by the valuation designee, reviews the Trust's valuation procedures and their application by the valuation designee, reviews pricing errors and procedures for calculation of net asset value of each series of the Trust and responds to other matters deemed appropriate by the board.

Governance Committee. Messrs. Neal, Rybak, Toub and Wennlund and Mses. Breen (Chair) and Stuckey serve on the governance committee. The governance committee operates under a written charter adopted and approved by the board. The governance committee oversees the independence and effective functioning of the Board of Trustees and endeavors to be informed about good practices for fund boards. It also makes recommendations to the board regarding compensation of independent trustees. The governance committee also functions as a nominating committee by making recommendations to the Board of Trustees regarding candidates for election as non- interested trustees. The governance committee looks to many sources for recommendations of qualified trustees, including current trustees, employees of Calamos Advisors, current shareholders of the Fund, search firms that are compensated for their services and other third-party sources. Any such search firm identifies and evaluates potential candidates, conducts screening interviews and provides information to the governance committee with respect to the individual candidates and the market for available candidates. In making trustee recommendations, the governance committee considers a number of factors, including a candidate's background, integrity, knowledge and relevant experience. These factors are set forth in an appendix to the committee's charter. Any prospective candidate is interviewed by the trustees and officers, and references are checked. The governance committee will consider shareholder recommendations regarding potential trustee candidates that are properly submitted to the governance committee for its consideration.

A Fund shareholder who wishes to propose a trustee candidate must submit any such recommendation in writing via regular mail to the attention of the Trust's Secretary, at the address of the Trust's principal executive offices. The shareholder recommendation must include:

● the number and class of all shares of the Trust's series owned beneficially or of record by the nominating shareholder at the time the recommendation is submitted and the dates on which such shares were acquired, specifying the number of shares owned beneficially;

● a full listing of the proposed candidate's education, experience (including knowledge of the investment company industry, experience as a director or senior officer of public or private companies, and directorships on other boards of other registered investment companies), current employment, date of birth, business and residence address, and the names and addresses of at least three professional references;

● information as to whether the candidate is, has been or may be an "interested person" (as such term is defined in the 1940 Act) of the Trust, Calamos Advisors or any of its affiliates, and, if believed not to be or have been an "interested person," information regarding the candidate that will be sufficient for the committee to make such determination;

● the written and signed consent of the candidate to be named as a nominee and to serve as a trustee of the Trust, if elected;

● a description of all arrangements or understandings between the nominating shareholder, the candidate and/or any other person or persons (including their names) pursuant to which the shareholder recommendation is being made, and if none, so specify;

● the class or series and number of all shares of the Trust's series owned of record or beneficially by the candidate, as reported by the candidate; and

● such other information that would be helpful to the governance committee in evaluating the candidate.

The governance committee may require the nominating shareholder to furnish other information it may reasonably require or deem necessary to verify any information furnished pursuant to the procedures delineated above or to determine the qualifications and eligibility of the candidate proposed by the nominating shareholder to serve as a trustee. If the nominating shareholder fails to provide such additional information in writing within seven days of receipt of written request from the governance committee, the recommendation of such candidate will be deemed not properly submitted for consideration, and the governance committee is not required to consider such candidate.

Unless otherwise specified by the governance committee's chairman or by legal counsel to the non-interested trustees, the Trust's Secretary will promptly forward all shareholder recommendations to the governance committee's chairman and the legal counsel to the non-interested trustees, indicating whether the shareholder recommendation has been properly submitted pursuant to the procedures adopted by the governance committee for the consideration of trustee candidates nominated by shareholders.

Recommendations for candidates as trustees will be evaluated, among other things, in light of whether the number of trustees is expected to change and whether the trustees expect any vacancies. During periods when the governance committee is not actively recruiting new trustees, shareholder recommendations will be kept on file until active recruitment is under way. After consideration of a shareholder recommendation, the governance committee may dispose of the shareholder recommendation.

In addition to the above committees, there is a valuation designee, appointed by the board of trustees, comprised of officers of the Trust and employees of Calamos Advisors.

The following table identifies the number of meetings the Board of Trustees and each committee held during the fiscal period ended July 31, 2024:

		NUMBER OF MEETINGS DURING FISCAL PERIOD ENDED JULY 31, 2024
Board			7
Executive Committee			0
Audit Committee			4
Governance Committee			2
Dividend Committee			0
Valuation Committee			4

LEADERSHIP STRUCTURE AND QUALIFICATIONS OF THE BOARD OF TRUSTEES. The Board of Trustees is responsible for oversight of the Trust. The Trust has engaged Calamos Advisors to manage the Fund on a day-to-day basis. The Board of Trustees oversees Calamos Advisors and certain other principal service providers in the operations of the Fund. The Board of Trustees is currently composed of seven members, six of whom are non-interested trustees. The Board of Trustees meets in-person at regularly scheduled meetings four times throughout the year. In addition, the board may meet in-person or by telephone at special meetings or on an informal basis at other times. As described above, the Board of Trustees has established five standing committees - Audit, Dividend, Executive, Governance and Valuation - and may establish ad hoc committees or working groups from time to time to assist the Board of Trustees in fulfilling its oversight responsibilities. The non-interested trustees also have engaged independent legal counsel to assist them in fulfilling their responsibilities. Such independent legal counsel also serves as counsel to the Trust.

The chairman of the Board of Trustees is an "interested person" of the Trust (as such term is defined in the 1940 Act). The non-interested trustees have appointed a lead independent trustee. The lead independent trustee serves as a liaison between Calamos Advisors and the non-interested trustees and leads the non-interested trustees in all aspects of their oversight of the Fund. Among other things, the lead independent trustee reviews and approves, with the chairman, the agenda for each board and committee meeting and facilitates communication among the Trust's non-interested trustees. The trustees believe that the board's leadership structure is appropriate given the characteristics and circumstances of the Trust. The trustees also believe that this structure facilitates the exercise of the board's independent judgment in fulfilling its oversight function and efficiently allocates responsibility among committees.

The Board of Trustees has concluded that, based on each trustee's experience, qualifications, attributes or skills on an individual basis and in combination with those of the other trustees, each trustee should serve as a member of the board. In making this determination, the board has taken into account the actual service of the trustees during their tenure in concluding that each should continue to serve. The board also has considered each trustee's background and experience. Set forth below is a brief discussion of the specific experience qualifications, attributes or skills of each trustee that led the board to conclude that he or she should serve as a trustee.

Each of Mses. Breen and Stuckey and Messrs. Calamos, Neal, Rybak, Toub, and Wennlund has more than 25 years of experience in the financial services industry. Each of Mses. Breen and Stuckey and Messrs. Calamos, Neal, Rybak, and Wennlund has experience serving on boards of other entities, including other investment companies. Each of Ms. Breen and Messrs. Calamos, Neal, Rybak and Toub has earned a Masters of Business Administration degree.

RISK OVERSIGHT. The operation of an ETF, including its investment activities, generally involves a variety of risks. As part of its oversight of the Fund, the Board of Trustees oversees risk through various regular board and committee activities. The Board of Trustees, directly or through its committees, reviews reports from, among others, Calamos Advisors, the Trust's Compliance Officer, the Trust's independent registered public accounting firm, outside legal counsel, and internal auditors of Calamos Advisors or its affiliates, as appropriate, regarding risks faced by the Fund and the risk management programs Calamos Advisors and certain service providers. The actual day-to-day risk management with respect to the Fund resides with Calamos Advisors and other service providers to the Fund. Although the risk management policies of Calamos Advisors and the service providers are designed to be effective, there is no guarantee that they will anticipate or mitigate all risks. Not all risks that may affect the Fund can be identified, eliminated or mitigated and some risks simply may not be anticipated or may be beyond the control of the Board of Trustees or Calamos Advisors, its affiliates or other service providers.

TRUSTEE AND OFFICER COMPENSATION. John P. Calamos, Sr., the trustee who is an "interested person" of the Trust, does not receive compensation from the Trust. Although they are compensated, the non-interested trustees do not receive any pension or retirement benefits from the Trust. Mr. Mickey is the only Trust officer who receives compensation from the Trust. The following table sets forth the total compensation (including any amounts deferred, as described below) paid by the Trust during the periods indicated to each of the current trustees and officers compensated by the Trust. As the Fund was not in operation as of the date of this SAI, no Trustee received any compensation from the Fund during that time.

NAME		AGGREGATE COMPENSATION FROM THE FUND(1)​			TOTAL COMPENSATION FROM CALAMOS FUNDS COMPLEX(2) ​8/1/23-7/31/24
John P. Calamos		$	0			$	0
Virginia G. Breen		$	[TO COME]			$	[TO COME]
John E. Neal(3)​		$	[TO COME]			$	[TO COME]	(4)​
William R. Rybak		$	[TO COME]			$	[TO COME]
Karen L. Stuckey		$	[TO COME]			$	[TO COME]
Christopher M. Toub		$	[TO COME]			$	[TO COME]
Lloyd A. Wennlund		$	[TO COME]			$	[TO COME]
Mark J. Mickey		$	[TO COME]			$	[TO COME]

(1) Estimated compensation to be paid to the Independent Trustees for the Fund's initial fiscal year ending July 31, 2025. In determining aggregate compensation to be paid by the Fund, any funds of the Trust that may be expected to incept after September [TO COME], 2024 have not been included in the calculation of the estimate. Accordingly, such estimate may be higher than actual expenses.

(2) Calamos Funds Complex consisted of 49 portfolios as of the end of the period indicated. It should be noted that no compensation is reflected for each Fund that did not launch before July 31, 2024.

(3) Includes fees deferred during the relevant period pursuant to a deferred compensation plan. Deferred amounts are treated as though such amounts have been invested and reinvested in shares of one or more of the Funds as selected by the trustee. As of July 31, 2024, the value of the deferred compensation account of Mr. Neal was $[TO COME].

(4) Includes compensation received from the Calamos Aksia Alternative Credit and Income Fund in the amount of $[TO COME]. Such compensation is subject to a different compensation schedule and allocation.

The compensation paid to the non-interested trustees of Calamos Funds for their services as such consists of an annual retainer fee in the amount of $210,000 (increased from $185,000, effective on January 1, 2024), with annual supplemental retainers of $40,000 to the lead independent trustee, $20,000 to the chair of the audit committee and $10,000 to the chair of any other committee. Each non-interested trustee receives a meeting attendance fee of $7,000 for any special board meeting attended in person or $3,500 for any special board meeting attended by telephone.

Compensation paid to the non-interested trustees is allocated among the series of the Calamos Funds in accordance with a procedure determined from time to time by the board.

The Trust has adopted a deferred compensation plan for non-interested trustees (the "Plan"). Under the Plan, a trustee who is not an "interested person" of Calamos Advisors and has elected to participate in the Plan (a "participating trustee") may defer receipt of all or a portion of his or her compensation from the Trust in order to defer payment of income taxes or for other reasons. The deferred compensation payable to the participating trustee is credited to the trustee's deferred compensation account as of the business day such compensation otherwise would have been paid to the trustee. The value of a trustee's deferred compensation account at any time is equal to what the value would be if the amounts credited to the account had instead been invested in shares of one or more of the Funds as designated by the trustee. Thus, the value of the account increases with contributions to the account or with increases in the value of the measuring shares, and the value of the account decreases with withdrawals from the account or with declines in the value of the measuring shares. If a participating trustee retires, the trustee may elect to receive payments under the plan in a lump sum or in equal annual installments over a period of five years. If a participating trustee dies, any amount payable under the Plan will be paid to the trustee's beneficiaries. The Fund's obligation to make payments under the Plan is a general obligation of that Fund. No Fund is liable for any other Fund's obligations to make payments under the Plan.

The Fund had not yet publicly offered any Fund Shares for sale prior to the date of this SAI. Accordingly, no trustee owned "beneficially" (within the meaning of that term as defined in Rule 16a-1(a)(2) under the 1934 Act) any Fund Shares of the Fund as of the date of this SAI. As of December 31, 2023, each trustee beneficially owned (as determined pursuant to Rule 16a-1(a)(2) under the Securities Exchange Act of 1934, as amended ("1934 Act")) fund Shares of all funds in the Fund Complex having values within the indicated dollar ranges.*

		AGGREGATE DOLLAR RANGE OF SHARES OF ALL FUNDS IN THE FUND COMPLEX
John P. Calamos, Sr.(1)​		Over $100,000
Virginia G. Breen		Over $100,000
John E. Neal		Over $100,000
William R. Rybak		Over $100,000
Karen L. Stuckey		Over $100,000
Christopher M. Toub		Over $100,000
Lloyd A. Wennlund		Over $100,000

(1) Pursuant to Rule 16a-1(a)(2) of the 1934 Act, John P. Calamos, Sr. may be deemed to have indirect beneficial ownership of Fund shares held by Calamos Investments LLC, its subsidiaries, and its parent companies (Calamos Asset Management, Inc. and Calamos Partners LLC, and its parent company Calamos Family Partners, Inc.) due to his direct or indirect ownership interest in those entities. As a result, these amounts reflect any holdings of those entities in addition to the individual, personal accounts of John P. Calamos, Sr.

* Valuation as of December 31, 2023.

CODE OF ETHICS. Personnel of Calamos Advisors and Calamos Financial Services LLC ("CFS"), the Funds' distributor, are permitted to make personal securities transactions, including transactions in securities that the Trust may purchase, sell or hold, subject to requirements and restrictions set forth in the Code of Ethics of the Trust and the Code of Ethics of Calamos Advisors and CFS. The Codes of Ethics adopted pursuant to Rule 17j-1 under the 1940 Act contain provisions and requirements designed to identify and address certain conflicts of interest between personal investment activities of Calamos Advisors and CFS personnel and the interests of investment advisory clients such as the Trust. Among other things, the Codes of Ethics prohibit certain types of transactions absent prior approval, impose time periods during which personal transactions may not be made in certain securities, and require the submission of duplicate broker confirmations and statements and quarterly reporting of securities transactions. Additional restrictions apply to portfolio managers, traders, research analysts and others involved in the investment advisory process. Exceptions to these and other provisions of the Codes of Ethics may be granted in particular circumstances after review by appropriate personnel.

Affiliates of Calamos Advisors and CFS, CAM, CILLC, Calamos Partners LLC ("CPL"), Calamos Family Partners, Inc. ("CFP") and the owners of these affiliates, which include John P. Calamos, Sr. and members of his family ("Calamos Family"), may invest in products managed by Calamos Advisors to support the continued growth of our investment products and strategies, including investments to seed new products. Notwithstanding any provision to the contrary in the Code of Ethics, investments and corresponding hedging transactions made by Calamos Advisors, CFS, CAM, CILLC, CPL, CFP and the Calamos Family in Calamos products (excluding Closed-End Funds and ETFs) are not subject to restrictions of the Code of Ethics, such as the short-term trading ban. However, these hedging transactions are subject to pre-clearance by the Corporate Investment Committee. Calamos Advisors' CCO and Funds' CCO are copied in the approval process. In addition, these entities do not receive preferential treatment over clients. (They may, however, be traded together with discretionary client transactions.).

The General Counsel may approve additional strategies or instruments based on unusual market circumstances and on the determination that the transactions would not impact the broader market or conflict with any customer activity.

PROXY VOTING PROCEDURES. The Fund has delegated proxy voting responsibilities to Calamos Advisors, subject to the board of trustees' general oversight. The Fund expects Calamos Advisors to vote proxies related to that Fund's portfolio securities for which the Fund has voting authority consistent with the Fund's best interests. Calamos Advisors has adopted its own Proxy Voting Policies and Procedures (the "Policies"). The Policies address, among other things, conflicts of interest that may arise between the Funds' interests, and the interests of Calamos Advisors and its affiliates.

The following is a summary of the Policies used by Calamos Advisors in voting proxies.

To assist it in voting proxies, Calamos Advisors has established a Proxy Review Committee ("committee") comprised of members of its Portfolio Management (which may include portfolio managers and/or research analysts), Operations, Legal and Compliance Departments. The committee and/or its members will vote proxies using the following guidelines.

In general, if Calamos Advisors believes that a company's management and board have interests sufficiently aligned with the Fund's interest, Calamos Advisors will vote in favor of proposals recommended by the company's board. More specifically, Calamos Advisors seeks to ensure that the board of directors of a company is sufficiently aligned with security holders' interests and provides proper oversight of the company's management. In many cases this may be best accomplished by having a majority of independent board members. Calamos generally prefers that key committees such as audit, nominating, and compensation committees be comprised of independent directors.

Because of the enormous variety and complexity of transactions that are presented to shareholders, such as mergers, acquisitions, reincorporations, adoptions of anti-takeover measures (including adoption of a shareholder rights plan, requiring supermajority voting on particular issues, adoption of fair price provisions, issuance of blank check preferred stocks and the creation of a separate class of stock with unequal voting rights), changes to capital structures (including authorizing additional shares, repurchasing stock or approving a stock split), executive compensation and option plans, that occur in a variety of industries, companies and market cycles, it is extremely difficult to foresee exactly what would be in the best interests of the Fund in all circumstances. Moreover, voting on such proposals involves considerations unique to each transaction. Accordingly, Calamos Advisors will vote on a case-by-case basis on proposals presenting these transactions.

Calamos Advisors has assigned its administrative duties with respect to the proxy analysis and voting decisions to the "Proxy Group" (the Investment team - research analysts and portfolio management), and administrative processing to its Corporate Actions Group within the Operations Department. To assist it in analyzing proxies, Calamos subscribes to Glass Lewis an unaffiliated third-party corporate governance research service that provides in-depth analyses of shareholder meeting agendas, and voting recommendations. Glass Lewis facilitates the voting of each proxy by applying Calamos' custom proxy voting rules ("proxy voting policy") to the proposal(s). Any proxy proposal that is not covered by the proxy voting guidelines is reviewed and considered by Calamos' proxy group and voted in accordance with that review. Calamos has two sets of custom proxy voting rules: environmental, social and governance ("ESG") proxy voting rules, and non-ESG proxy voting rules.

Finally, Calamos Advisors has established procedures to help resolve conflicts of interests that might arise when voting proxies for the Funds. Calamos will generally apply its proxy voting policy to proxy proposals regardless of whether a conflict has been identified. However, in these situations, the Proxy Group will refer the proxy proposal, along with the recommended course of action, if any, to the Proxy Review Committee or a subcommittee thereof (each, a "committee") for evaluation. The committee will independently review the proposals and determine the appropriate action to be taken. The committee will then memorialize the conflict and the procedures used to address the conflict.

The Trust is required to file with the SEC on Form N-PX its complete proxy voting record for the 12-month period ending June 30, by no later than August 31 of each year. The Trust's proxy voting record for the most recent 12-month period ending June 30 will be available by August 31 of each year (1) on the SEC's website at www.sec.gov, and (2) on the Calamos Funds' website at www.calamos.com, and (3) without charge, upon request, by calling 866.363.9219 or emailing [email protected].

You may obtain a copy of Calamos Advisors' Policies by calling 866.363.9219 or by writing Calamos Advisors at: Calamos Investments, Attn: Client Services, 2020 Calamos Court, Naperville, IL 60563, and on the SEC's website at www.sec.gov.

DISCLOSURE OF PORTFOLIO HOLDINGS. The Trust has adopted a policy regarding the disclosure of information about the Trust's portfolio holdings. The Board must approve all material amendments to this policy. The Fund's portfolio holdings are publicly disseminated each day the Fund is open for business through financial reporting and news services including publicly accessible Internet web sites. In addition, a basket composition file, which includes the security names and share quantities to deliver in exchange for Fund Shares, together with estimates and actual cash components, is publicly disseminated daily prior to the opening of the Exchange via the National Securities Clearing Corporation ("NSCC"). The basket represents one Creation Unit of the Fund. The Trust and Calamos Advisors will not disseminate non-public information concerning the Trust.

Calamos Advisors and CFS carry out the policies and procedures governing disclosure of portfolio security holdings, and as such have access to information regarding portfolio security holdings on a daily basis and may disclose that information to the Fund's service providers and other third parties only in accordance with the policies and procedures adopted by the Board of Trustees.

NON-PUBLIC DISCLOSURE

Disclosures required by Applicable Law. The Funds, Calamos Advisors and CFS may disclose portfolio security holdings information of the Fund as may be required by applicable law, rule, regulation or court order. Any officer of the Fund, Calamos Advisors or CFS is authorized to disclose portfolio security holdings pursuant to these policies and procedures.

As part of the Fund's compliance program under Rule 38a-1 under the 1940 Act, the Trust's Chief Compliance Officer periodically will review or cause to be reviewed portfolio security holding disclosures in order to seek compliance with these policies and procedures. The Board of Trustees oversees disclosures through the reporting of the Chief Compliance Officer.

The Fund, Calamos Advisors and CFS do not receive compensation or other consideration for the disclosure of portfolio security holdings.

CONTROL PERSONS AND PRINCIPAL HOLDERS OF SECURITIES

A principal shareholder is any person who owns (either of record or beneficially) 5% or more of the outstanding Fund Shares of the Fund. A control person is one who owns, either directly or indirectly, more than 25% of the voting securities of a company or acknowledges the existence of control.

INVESTMENT ADVISORY SERVICES

Investment Adviser

Investment management and certain other services are provided to the Trust by Calamos Advisors pursuant to a Management Agreement (the "Management Agreement") dated September 1, 2023, as amended. Calamos Advisors also furnishes office space, equipment and management personnel to the Trust.

The Fund pays Calamos Advisors a fee based on its average daily net assets that is accrued daily and paid on a quarterly basis. The Fund pays a fee on its average daily net assets at the annual rate of 0.10% on average daily net assets.

With respect to a Fund in the Calamos Family of Funds (each an "Acquiring Fund") that invests in Fund Shares of Calamos Laddered S&P 500 Structured Alt Protection ETF, Calamos Advisors agrees to waive an amount equal to the portion of the advisory fee payable to the Fund that is attributable to the Acquiring Fund's investment in the Fund, based on daily net assets.

Calamos Advisors is a wholly owned subsidiary of Calamos Investments LLC ("CILLC"). Calamos Asset Management, Inc. ("CAM") is the sole manager of CILLC. As of December 31, 2023, approximately 22% of the outstanding interests of CILLC was owned by CAM and the remaining approximately 78% of CILLC was owned by Calamos Partners LLC ("CPL") and John P. Calamos, Sr. CAM was owned by John P. Calamos, Sr. and John S. Koudounis, and CPL was owned by John S. Koudounis and Calamos Family Partners, Inc. ("CFP"). CFP was beneficially owned by members of the Calamos family, including John P. Calamos, Sr. In addition, Mr. Koudounis has the option to purchase a controlling interest in CPL upon the death or permanent disability of John P. Calamos, Sr., provided Mr. Koudounis is then serving as Chief Executive Officer of CAM and CILLC. John P. Calamos, Sr., is an affiliated person of the Fund and Calamos Advisors by virtue of his position as Chairman, Trustee and President of the Trust and Chairman and Global Chief Investment Officer ("Global CIO") of Calamos Advisors. John S. Koudounis, Robert F. Behan, Thomas E. Herman, Erik D. Ojala, Stephen Atkins and Daniel Dufresne are affiliated persons of the Fund and Calamos Advisors by virtue of their positions as Vice President; Vice President; Vice President and Chief Financial Officer; Vice President and Secretary; Treasurer; and Vice President of the Trust; respectively, and as President and Chief Executive Officer; Executive Vice President and Chief Distribution Officer; Executive Vice President and Chief Financial Officer; Senior Vice President, General Counsel and Secretary; Senior Vice President and Head of Fund Administration; and Executive Vice President and Chief Operating Officer of Calamos Advisors, respectively.

The use of the name "Calamos" in the name of the Trust and in the name of the Funds are pursuant to licenses granted by Calamos Investments LLC, and the Trust has agreed to change the names to remove those references if Calamos Advisors ceases to act as Adviser to the Funds.

EXPENSES

Out of its management fee, the Adviser pays substantially all expenses of the Fund, including the cost of transfer agency, custody, fund administration, legal, audit and other service and license fees, except for distribution and service fees payable pursuant to a Rule 12b-1 plan, if any, acquired fund fees and expenses brokerage commissions and other expenses connected with the execution of portfolio transactions, taxes, interest, and extraordinary expenses.

Fees and expenses related to the Fund's organization and registration and qualification of the Fund and its Fund Shares under federal and state securities laws will be borne by the Adviser.

MANAGEMENT APPROACH

Calamos Advisors employs a "team of teams" approach to portfolio management, led by the Global CIO and our CIO team consisting of five (5) Co-CIOs with specialized areas of investment expertise. The Global CIO and Co-CIO team are responsible for oversight of investment team resources, investment processes, performance and risk. As heads of investment verticals, Co-CIOs manage investment team members and, along with Co-Portfolio Managers and Associate Portfolio Managers, have day-to-day portfolio oversight and construction responsibilities of their respective investment strategies. While investment research professionals within each Co-CIO's team are assigned specific strategy responsibilities, they also provide support to other investment team verticals, creating deeper insights across a wider range of investment strategies. The combination of specialized investment teams with cross-team collaboration results in what we call our team of teams approach.

This team of teams approach is further reflected in the composition of Calamos Advisors' Investment Committee, made up of the Global CIO, the Co-CIO team, and the Global Head of Trading. Other members of the investment team participate in Investment Committee meetings in connection with specific investment related issues or topics as deemed appropriate.

The structure and composition of the Investment Committee results in a number of benefits, as it:

● Leads to broader perspective on investment decisions: multiple viewpoints and areas of expertise feed into consensus;

● Promotes collaboration between teams; and

● Functions as a think tank with the goal of identifying ways to outperform the market on a risk-adjusted basis.

The objectives of the Investment Committee are to:

● Form the firm's top-down macro view, market direction, asset allocation, and sector/country positioning.

● Establish firm-wide secular and cyclical themes for review.

● Review firm-wide and portfolio risk metrics, recommending changes where appropriate.

● Review firm-wide, portfolio and individual security liquidity constraints.

● Evaluate firm-wide and portfolio investment performance.

● Evaluate firm-wide and portfolio hedging policies and execution.

● Evaluate enhancements to the overall investment process.

David O'Donohue, Jimmy Young, Eli Pars, Jason Hill, and Anthony Vecchiolla are the Funds' portfolio managers and are collectively referred to within this registration statement as "Portfolio Managers". The Portfolio Managers have responsibility for allocating the portfolio across the market capitalization spectrum, sectors, and geographies within the portfolio's eligible investment universe and for reviewing the overall composition of the portfolio to ensure compliance with its stated investment objective. The Portfolio Managers, in collaboration with other members of the Calamos Advisors investment teams, have the responsibility of overseeing the integration of the Fund's investment approach and framework to ensure compliance with the Fund's stated investment approach.

The Portfolio Managers also have responsibility for the day-to-day management of accounts other than the Fund. Information regarding these other accounts as of July 31, 2024 is set forth below.

Other Accounts Managed and Assets by Account Type as of July 31, 2024

REGISTERED INVESTMENT COMPANIES

OTHER POOLED INVESTMENT VEHICLES

OTHER ACCOUNTS

ACCOUNTS

ASSETS

ACCOUNTS

ASSETS

ACCOUNTS

ASSETS

David O'Donohue

Jimmy Young

-

-

Eli Pars

-

-

Jason Hill

-

-

Anthony Vecchiolla

-

-

Number of Accounts and Assets for which Advisory Fee is Performance Based as of _______, 202[ ]

REGISTERED INVESTMENT COMPANIES

OTHER POOLED INVESTMENT VEHICLES

OTHER ACCOUNTS

ACCOUNTS

ASSETS

ACCOUNTS

ASSETS

ACCOUNTS

ASSETS

David O'Donohue

-

-

Jimmy Young

-

-

-

Eli Pars

-

-

-

Jason Hill

-

-

-

Anthony Vecchiolla

-

-

-

The Portfolio Managers may invest for their own benefit in securities held in brokerage and fund accounts. The information shown in the table does not include information about those accounts where the Portfolio Managers or members of their family have a beneficial or pecuniary interest because no advisory relationship exists with Calamos Advisors or any of its affiliates.

The Fund's Portfolio Managers are responsible for managing both the Fund and other accounts, including separate accounts.

Other than potential conflicts between investment strategies, the side-by-side management of both the Fund and other accounts may raise potential conflicts of interest due to the interest held by Calamos Advisors in an account and certain trading practices used by the portfolio managers (e.g., cross trades between the Fund and another account and allocation of aggregated trades). Calamos Advisors has developed policies and procedures reasonably designed to mitigate those conflicts. For example, Calamos Advisors will only place cross-trades in securities held by the Fund in accordance with the rules promulgated under the 1940 Act and has adopted policies designed to ensure the fair allocation of securities purchased on an aggregated basis. The allocation methodology employed by Calamos Advisors varies depending on the type of securities sought to be bought or sold and the type of client or group of clients. Generally, however, orders are placed first for those clients that have given Calamos Advisors brokerage discretion (including the ability to step out a portion of trades), and then to clients that have directed Calamos Advisors to execute trades through a specific broker. However, if the directed broker allows Calamos Advisors to execute with other brokerage firms, which then book the transaction directly with the directed broker, the order will be placed as if the client had given Calamos Advisors full brokerage discretion. Calamos Advisors and its affiliates frequently use a "rotational" method of placing and aggregating client orders and will build and fill a position for a designated client or group of clients before placing orders for other clients.

A client account may not receive an allocation of an order if: (a) the client would receive an unmarketable amount of securities based on account size; (b) the client has precluded Calamos Advisors from using a particular broker; (c) the cash balance in the client account will be insufficient to pay for the securities allocated to it at settlement; (d) current portfolio attributes make an allocation inappropriate; and (e) account specific guidelines, objectives and other account specific factors make an allocation inappropriate. Allocation methodology may be modified when strict adherence to the usual allocation is impractical or leads to inefficient or undesirable results. Calamos Advisors' head trader must approve each instance that the usual allocation methodology is not followed and provide a reasonable basis for such instances and all modifications must be reported in writing to Calamos Advisors' Chief Compliance Officer on a monthly basis. Investment opportunities for which there is limited availability generally are allocated among participating client accounts pursuant to an objective methodology (i.e., either on a pro rata basis or using a rotational method, as described above). However, in some instances, Calamos Advisors may consider subjective elements in attempting to allocate a trade, in which case the Fund may not participate, or may participate to a lesser degree than other clients, in the allocation of an investment opportunity. In considering subjective criteria when allocating trades, Calamos Advisors is bound by its fiduciary duty to its clients to treat all client accounts fairly and equitably.

As of March 31, 2024, Messrs. O'Donohue, Young, Pars, Hill, and Vecchiolla receive all of their compensation from Calamos Advisors. Compensation for portfolio management team members includes a competitive base salary, and an annual cash bonus (driven by investment, company, and individual performance). Portfolio managers are also eligible for Calamos Advisors' Long-Term Incentive ("LTI") program, which is an incentive award vesting over time that reflects appreciation and depreciation in the value of both the funds managed by such professional and the company generally. LTI awards granted in 2023 vest on a three-year schedule (25% on or about the first anniversary of the award grant, 25% on or about the second anniversary of the award grant, and 50% on or about the third anniversary of the award grant). Each investment team LTI award will be allocated as follows: (i) 33.3% to track the value of the associate's managed strategies, (ii) 33.3% to track the Calamos strategy of the associate's choice, and (iii) 33.3% to track the value of the firm; all over the vesting period.

The existence of these separate asset or fee-based payments could create a conflict of interest with regard to each portfolio manager's allocation of investment opportunities among the accounts for which they act as portfolio manager. Calamos Advisors maintains policies and procedures reasonably designed to mitigate such conflicts of interest.

This compensation structure considers annually the performance of the various strategies managed by the portfolio managers, among other factors, including, without limitation, the overall performance of the firm.

The Fund had not yet publicly offered any Fund Shares for sale prior to the date of this SAI. Accordingly, the portfolio managers do not own any Fund Shares of the Funds as of the date of this SAI.

DISTRIBUTOR

The Fund's distributor is Calamos Financial Services LLC ("CFS" or the "Distributor"), 2020 Calamos Court, Naperville, Illinois, 60563. The Distributor has entered into a distribution agreement (the "Distribution Agreement") with the Trust pursuant to which it distributes Fund Shares.

Fund Shares will be continuously offered for sale by the Trust through the Distributor only in Creation Units, as described below under "Transactions in Creation Units." Fund Shares in less than Creation Units are not distributed by the Distributor. The Distributor also acts as agent for the Trust. The Distributor will deliver a Prospectus to persons purchasing Fund Shares in Creation Units and will maintain records of both orders placed with it and confirmations of acceptance furnished by it. The Distributor is a broker-dealer registered under the 1934 Act and a member of the Financial Industry Regulatory Authority, Inc.

The Distributor has no role in determining the investment policies of the Funds, or which securities are to be purchased or sold by the Funds.

12b-1 Plan. The Board has adopted a distribution and service plan ("Distribution and Service Plan") pursuant to Rule 12b-1 under the Investment Company Act ("Plan"). In accordance with its Plan, the Fund is authorized to pay an amount up to 0.25% of its average daily net assets each year for certain distribution-related activities. In addition, if the payment of management fees by the Fund is deemed to be indirect financing by the Fund of the distribution of its Fund Shares, such payment is authorized by the Plan. Calamos Advisors may use management fee revenue, as well as past profits or other resources, to pay for expenses incurred in connection with providing services intended to result in the sale of Fund Shares. Calamos Advisors may pay amounts to third parties for distribution or marketing services on behalf of the Fund.

The Plan was adopted in order to permit the implementation of the Fund's method of distribution. No fees are currently paid by the Fund under the Plan, however, and there are no current plans to impose such fees. In the event such fees were to be charged, over time they would increase the cost of an investment in the Fund because they would be paid on an ongoing basis. If fees were charged under the Plan, the Trustees would receive and review at the end of each quarter a written report provided by the Distributor of the amounts expended under the Plan and the purpose for which such expenditures were made.

The Plan will remain in effect for a period of one year and is renewable from year to year with respect to the Fund, so long as its continuance is approved at least annually (1) by the vote of a majority of the Trustees and (2) by a vote of the majority of the independent trustees, cast in person at a meeting called for the purpose of voting on such approval. The Plan may not be amended to increase materially the amount of fees paid by the Fund unless such amendment is approved by majority vote of the outstanding Fund Shares and by the independent trustees in the manner described above. The Plan is terminable with respect to the Fund at any time by a vote of a majority of the independent trustees or by 1940 Act majority vote of the outstanding Fund Shares.

OTHER COMPENSATION TO INTERMEDIARIES

Calamos Advisors and its affiliates are currently subject to supplemental compensation payment requests by certain securities broker-dealers, banks or other intermediaries, including third party administrators of qualified plans (each an "Intermediary") whose customers have purchased Fund Shares. In their discretion, Calamos Advisors and its affiliates may make payments to an Intermediary for various purposes. These payments do not increase the amount paid by you or the Fund, as they are paid from the legitimate profits from these entities in what is generally referred to as "revenue sharing."

Revenue sharing payments are generally a percentage of the account's average annual net assets. Calamos Advisors and its affiliates may make these payments to an Intermediary for various purposes, including to help defray costs incurred by the Intermediary to educate financial advisers about the Fund so they can make recommendations and provide services that are suitable and meet shareholder needs, to access the Intermediary's representatives, to provide marketing support and other specified services. To the extent that the Fund does not pay for these costs directly, Calamos Advisors and its affiliates may also make payments to certain financial intermediaries for administrative services such as record keeping, sub-accounting for shareholder accounts, client account maintenance support, statement preparation, transaction processing, payment of ticket charges per purchase or exchange order placed by a financial intermediary, payment of networking fees in connection with certain trading systems, or one-time payments for services such as setting up the Fund on a intermediary's trading system.

In addition, Calamos Advisors and its affiliates may also share certain marketing expenses with intermediaries, or pay for or sponsor informational meetings, seminars, client awareness events, support for marketing materials, sales reporting, or business building programs for such financial intermediaries to raise awareness of the Fund. Calamos Advisors and its affiliates may make payments to participate in intermediary marketing support programs which may provide Calamos Advisors, as applicable, with one or more of the following benefits: attendance at sales conferences, participation in meetings or training sessions, access to or information about intermediary personnel, use of an intermediary's marketing and communication infrastructure, fund analysis tools, data and data analytics, business planning and strategy sessions with intermediary personnel, information on industry- or platform specific developments, trends and service providers, and other marketing-related services. Such payments may be in addition to, or in lieu of, the payments described above. These payments are intended to promote the sales of the Fund and to reimburse financial intermediaries, directly or indirectly, for the costs that they or their salespersons incur in connection with educational seminars, meetings, and training efforts about the Fund to enable the intermediaries and their salespersons to make suitable recommendations, provide useful services, and maintain the necessary infrastructure to make the Fund available to their customers.

These payments may provide Intermediaries with an incentive to favor Fund Shares of the Fund over sales of shares of other ETFs or non-ETF investments. These payments may influence the Intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your Intermediary's website for more information. You may wish to take such payment arrangements into account when considering and evaluating any recommendations relating to Fund Shares and you should discuss this matter with your Intermediary and its representatives. The Fund may utilize an Intermediary that offers and sells Fund Shares to execute portfolio transactions for the Fund. The Funds and Calamos Advisors do not consider sales of Fund Shares as a factor in the selection of broker-dealers to execute portfolio transactions for the Fund.

PORTFOLIO TRANSACTIONS

Calamos Advisors is responsible for decisions to buy and sell securities for the Fund, the selection of brokers and dealers to effect the transactions and the negotiation of prices and any brokerage commissions on such transactions.

Portfolio transactions on behalf of the Fund effected on stock exchanges involve the payment of negotiated brokerage commissions. There is generally no stated commission in the case of securities traded in the OTC markets, but the price the Fund pays usually includes an undisclosed dealer commission or mark-up. For securities purchased in an underwritten offering, the price the Fund pays includes a disclosed, fixed commission or discount retained by the underwriter or dealer.

In executing portfolio transactions, Calamos Advisors uses its best efforts to obtain for the Fund the most favorable combination of price and execution available. In seeking the most favorable combination of price and execution, Calamos Advisors considers all factors it deems relevant, including price, the size of the transaction, the nature of the market for the security, the amount of commission, the timing of the transaction taking into account market prices and trends, the execution capability of the broker- dealer and the quality of service rendered by the broker-dealer in other transactions.

In allocating the Fund's portfolio brokerage transactions to unaffiliated broker-dealers, Calamos Advisors may take into consideration the research, analytical, statistical and other information and services provided by the broker-dealer, such as general economic reports and information, reports or analyses of particular companies or industry groups, market timing and technical information, and the availability of the brokerage firm's analysts for consultation. Although Calamos Advisors believes these services have substantial value, they are considered supplemental to Calamos Advisors' own efforts in performing its duties under the Management Agreement.

Calamos Advisors does not guarantee any broker the placement of a predetermined amount of securities transactions in return for the research or brokerage services it provides. Calamos Advisors does, however, have internal procedures for allocating transactions in a manner consistent with its execution policies to brokers that it has identified as providing research, research-related products or services, or execution-related services of a particular benefit to its clients. Calamos Advisors has entered into client commission agreements ("CCAs") with certain broker-dealers under which the broker-dealers may use a portion of their commissions to pay third parties or other broker-dealers that provide Calamos Advisors with research or brokerage services, as permitted under Section 28(e) of the Exchange Act. CCAs allow Calamos Advisors to direct broker-dealers to pool commissions that are generated from orders executed at that broker-dealer, and then periodically direct the broker-dealer to pay third parties or other broker-dealers for research or brokerage services. All uses of CCAs by Calamos Advisors are subject to applicable law and their best execution obligations. Brokerage and research products and services furnished by brokers may be used in servicing any or all of the clients of Calamos Advisors and such research may not necessarily be used by Calamos Advisors in connection with the accounts which paid commissions to the broker providing such brokerage and research products and services.

As permitted by Section 28(e) of the 1934 Act, Calamos Advisors may pay a broker-dealer that provides brokerage and research services an amount of commission for effecting a securities transaction for the Fund in excess of the commission that another broker-dealer would have charged for effecting that transaction if Calamos Advisors believes the amount to be reasonable in relation to the value of the overall quality of the brokerage and research services provided. Other clients of Calamos Advisors may indirectly benefit from the availability of these services to Calamos Advisors, and the Fund may indirectly benefit from services available to Calamos Advisors as a result of research services received by Calamos Advisors through transactions for other clients. In addition, Calamos Advisors may execute portfolio transactions for the Fund, to the extent permitted by law, through broker-dealers affiliated with the Fund, Calamos Advisors, CFS, or other broker-dealers distributing Fund Shares of the Fund if it reasonably believes that the combination of price and execution is at least as favorable as with unaffiliated broker-dealers, and in such transactions any such broker-dealer would receive brokerage commissions paid by the Fund.

In certain cases, Calamos Advisors may obtain products or services from a broker that have both research and non-research uses. Examples of non-research uses are administrative and marketing functions. These are referred to as "mixed use" products. In each case, Calamos Advisors makes a good faith effort to determine the proportion of such products or services that may be used for research and non-research purposes. That determination is based upon the time spent by Calamos Advisors personnel for research and non-research uses. The portion of the costs of such products or services attributable to research usage may be defrayed by Calamos Advisors through brokerage commissions generated by transactions of its clients, including the Fund. Calamos Advisors pays the provider in cash for the non-research portion of its use of these products or services.

ADDITIONAL INFORMATION CONCERNING THE FUND SHARES

Organization and Description of Shares of Beneficial Interest

The Trust is a Delaware statutory trust and registered open-end investment company. The Trust was organized on June 17, 2013, and has authorized capital of unlimited Fund Shares of beneficial interest of no-par value that may be issued in more than one class or series. Currently, the Trust consists of eight actively managed series. The Board of Trustees may designate additional series.

Under Delaware law, the Trust is not required to hold an annual shareholders' meeting if the 1940 Act does not require such a meeting. Shareholders holding two-thirds of Fund Shares outstanding of the relevant Fund may remove Trustees from office by votes cast at a meeting of Trust shareholders or by written consent.

All Fund Shares are freely transferable. Fund Shares will not have preemptive rights or cumulative voting rights, and none of the Fund Shares will have any preference to conversion, exchange, dividends, retirements, liquidation, redemption, or any other feature. Fund Shares have equal voting rights. The Trust Instrument confers upon the Board the power, by resolution, to alter the number of Fund Shares constituting a Creation Unit or to specify that Fund Shares of the Fund may be individually redeemable. The Trust reserves the right to adjust the stock prices of Fund Shares to maintain convenient trading ranges for investors. Any such adjustments would be accomplished through stock splits or reverse stock splits that would have no effect on the NAV of the Fund.

The Trust Instrument of the Trust disclaims liability of the shareholders or the officers of the Trust for acts or obligations of the Trust that are binding only on the assets and property of the Trust. The Trust Instrument provides for indemnification out of the Fund's property for all loss and expense of the Fund's shareholders being held personally liable solely by reason of his or her being or having been a shareholder and not because of his or her acts or omissions or for some other reason. The risk of a Trust shareholder incurring financial loss on account of shareholder liability is limited to circumstances in which the Fund itself would not be able to meet the Trust's obligations and this risk should be considered remote.

If the Fund does not grow to a size to permit it to be economically viable, the Fund may cease operations. In such an event, shareholders may be required to liquidate or transfer their Fund Shares at an inopportune time and shareholders may lose money on their investment.

Book Entry Only System

The following information supplements, and should be read in conjunction with, the section in the Prospectus entitled "Fund Facts - Book Entry."

The Depository Trust Company ("DTC") acts as Securities Depository for Fund Shares. Fund Shares of the Fund are represented by securities registered in the name of DTC or its nominee and deposited with, or on behalf of, DTC.

DTC, a limited purpose trust company, was created to hold securities of its participants (the "DTC Participants") and to facilitate the clearance and settlement of securities transactions among the DTC Participants in such securities through electronic book entry changes in accounts of the DTC Participants, thereby eliminating the need for physical movement of securities certificates. DTC Participants include securities brokers and dealers, banks, trust companies, clearing corporations and certain other organizations, some of whom (and/or their representatives) own DTC. More specifically, DTC is owned by a number of its DTC Participants and by NYSE and FINRA. Access to the DTC system is also available to others such as banks, brokers, dealers and trust companies that clear through or maintain a custodial relationship with a DTC Participant, either directly or indirectly (the "Indirect Participants").

Beneficial ownership of Fund Shares is limited to DTC Participants, Indirect Participants and persons holding interests through DTC Participants and Indirect Participants. Ownership of beneficial interests in Fund Shares (owners of such beneficial interests are referred to herein as "Beneficial Owners") is shown on, and the transfer of ownership is effected only through, records maintained by DTC (with respect to DTC Participants) and on the records of DTC Participants (with respect to Indirect Participants and Beneficial Owners that are not DTC Participants). Beneficial Owners will receive from or through the DTC Participant written confirmation relating to their purchase and sale of Fund Shares.

Conveyance of all notices, statements and other communications to Beneficial Owners is effected as follows. Pursuant to the Depositary Agreement between the Trust and DTC, DTC is required to make available to the Trust upon request and for a fee to be charged to the Trust a listing of the Fund Shares of the Fund held by each DTC Participant. The Trust shall inquire of each such DTC Participant as to the number of Beneficial Owners holding Fund Shares, directly or indirectly, through such DTC Participant. The Trust shall provide each such DTC Participant with copies of such notice, statement or other communication, in such form, number and at such place as such DTC Participant may reasonably request, in order that such notice, statement or communication may be transmitted by such DTC Participant, directly or indirectly, to such Beneficial Owners. In addition, the Trust shall pay to each such DTC Participant a fair and reasonable amount as reimbursement for the expenses attendant to such transmittal, all subject to applicable statutory and regulatory requirements.

Fund distributions shall be made to DTC or its nominee, Cede & Co., as the registered holder of all Fund Shares. DTC or its nominee, upon receipt of any such distributions, shall immediately credit DTC Participants' accounts with payments in amounts proportionate to their respective beneficial interests in Fund Shares of the Fund as shown on the records of DTC or its nominee. Payments by DTC Participants to Indirect Participants and Beneficial Owners of Fund Shares held through such DTC Participants will be governed by standing instructions and customary practices, and will be the responsibility of such DTC Participants.

The Trust has no responsibility or liability for any aspect of the records relating to or notices to Beneficial Owners, or payments made on account of beneficial ownership interests in such Fund Shares, or for maintaining, supervising or reviewing any records relating to such beneficial ownership interests, or for any other aspect of the relationship between DTC and the DTC Participants or the relationship between such DTC Participants and the Indirect Participants and Beneficial Owners owning through such DTC Participants.

DTC may decide to discontinue providing its service with respect to Fund Shares at any time by giving reasonable notice to the Trust and discharging its responsibilities with respect thereto under applicable law. Under such circumstances, the Trust shall take action to find a replacement for DTC to perform its functions at a comparable cost.

The Trust is required to disclose on a quarterly basis the complete schedule of the Fund's portfolio holdings with the SEC on Form N-PORT. Form N-PORT for the Trust is available on the SEC's website at https://www.sec.gov. The Fund's Form N-PORT may also be reviewed and copied at the SEC's Public Reference Room in Washington, D.C. and information on the operation of the Public Reference Room may be obtained by calling 1-800-SEC-0330. The Trust's Forms N-PORT are available without charge, upon request, by calling (866) 363-9219 or by writing to Calamos ETF Trust, 2020 Calamos Court, Naperville, IL 60563.

CREATION AND REDEMPTION OF CREATION UNITS

General

The Fund will issue and sell Fund Shares only in Creation Units on a continuous basis, without an initial sales load, at their NAV next determined after receipt, on any Business Day (as defined herein), of an order in proper form. An Authorized Participant (defined below) that is not "qualified institutional buyer," as such term is defined under Rule 144A of the Securities Act, will not be able to receive, as part of a redemption, restricted securities eligible for resale under Rule 144A.

A "Business Day" with respect to the Fund is any day on which the NYSE is open for business. As of the date of this SAI, the NYSE observes the following holidays: New Year's Day, Martin Luther King, Jr. Day, President's Day (Washington's Birthday), Good Friday, Memorial Day (observed), Juneteenth National Independence Day, Independence Day, Labor Day, Thanksgiving Day and Christmas Day.

Distribution of Fund Shares

In connection with its launch, the Fund was seeded through the sale of one or more Creation Units to one or more initial investors. Initial investors participating in the seeding may be Authorized Participants or a lead market maker, other third party investor or an affiliate of the Fund or the Adviser purchasing from an Authorized Participant. Each such initial investor may sell some or all of the Fund Shares underlying the Creation Unit(s) held by them pursuant to the registration statement for the Fund (each, a "Selling Shareholder"), which Fund Shares have been registered to permit the resale from time to time after purchase. No Fund will receive any of the proceeds from the resale by the Selling Shareholders of these Fund Shares. Selling Shareholders may sell Fund Shares owned by them directly or through broker-dealers, in accordance with applicable law, on any national securities exchange on which the Fund Shares may be listed or quoted at the time of sale, through trading systems, in the over-the-counter market or in transactions other than on these exchanges or systems at fixed prices, at prevailing market prices at the time of the sale, at varying prices determined at the time of sale, or at negotiated prices. These sales may be effected through brokerage transactions, privately negotiated trades, block sales, entry into options or other derivatives transactions or through any other means authorized by applicable law. Selling Shareholders may redeem the Fund Shares held in Creation Unit size by them through an Authorized Participant. Any Selling Shareholder and any broker-dealer or agents participating in the distribution of Fund Shares may be deemed to be "underwriters" within the meaning of Section 2(a)(11) of the Securities Act, in connection with such sales. Any Selling Shareholder and any other person participating in such distribution will be subject to any applicable provisions of the Exchange Act and the rules and regulations thereunder.

Fund Deposit

The consideration for purchase of a Creation Unit of the Fund generally consists of the in-kind deposit of a designated portfolio of securities (the "Deposit Securities") per each Creation Unit, and the Cash Component (defined below), computed as described below. The Trust reserves the right to permit or require the substitution of Deposit Cash to be added to the Cash Component to replace any Deposit Security. When accepting purchases of Creation Units for all or a portion of Deposit Cash, the Fund may incur additional costs associated with the acquisition of Deposit Securities that would otherwise be provided by an in-kind purchaser.

Together, the Deposit Securities or Deposit Cash, as applicable, and the Cash Component constitute the "Fund Deposit," which represents the minimum initial and subsequent investment amount for a Creation Unit of the Fund. The "Cash Component" is an amount equal to the difference between the NAV of Fund Shares (per Creation Unit) and the value of the Deposit Securities or Deposit Cash, as applicable. If the Cash Component is a positive number (i.e., the NAV per Creation Unit exceeds the value of the Deposit Securities or Deposit Cash, as applicable), the Cash Component shall be such positive amount. If the Cash Component is a negative number (i.e., the NAV per Creation Unit is less than the value of the Deposit Securities or Deposit Cash, as applicable), the Cash Component shall be such negative amount and the creator will be entitled to receive cash in an amount equal to the Cash Component. The Cash Component serves the function of compensating for any differences between the NAV per Creation Unit and the value of the Deposit Securities or Deposit Cash, as applicable. Computation of the Cash Component excludes any stamp duty or other similar fees and expenses payable upon transfer of beneficial ownership of the Deposit Securities, if applicable, which shall be the sole responsibility of the Authorized Participant.

The Fund, through NSCC, make available on each Business Day, prior to the opening of business on the Exchange (currently 9:30 a.m., Eastern Time), the list of the names and the required number of Fund Shares of each Deposit Security or the required amount of Deposit Cash, as applicable, to be included in the current Fund Deposit (based on information at the end of the previous Business Day) for the Fund. Such Fund Deposit is subject to any applicable adjustments as described below, to effect purchases of Creation Units of the Fund until such time as the next-announced composition of the Deposit Securities or the required amount of Deposit Cash, as applicable, is made available.

The identity and number of Fund Shares of the Deposit Securities or the amount of Deposit Cash, as applicable, required for the Fund Deposit for the Fund changes as rebalancing adjustments and corporate action events are reflected from time to time by the Adviser with a view to the investment objective of the Fund.

The Trust reserves the right to permit or require the substitution of Deposit Cash to replace any Deposit Security, which shall be added to the Cash Component, including, without limitation, in situations where the Deposit Security: (i) may not be available in sufficient quantity for delivery; (ii) may not be eligible for transfer through the systems of DTC for corporate securities and municipal securities; (iii) may not be eligible for trading by an Authorized Participant or the investor for which it is acting; (iv) would be restricted under the securities laws or where the delivery of the Deposit Security to the Authorized Participant would result in the disposition of the Deposit Security by the Authorized Participant becoming restricted under the securities laws; or (v) in certain other situations (collectively, "custom orders"). The adjustments described above will reflect changes known to the Adviser on the date of announcement to be in effect by the time of delivery of the Fund Deposit from certain corporate actions.

Procedures for Purchase of Creation Units

To be eligible to place orders with the Transfer Agent to purchase a Creation Unit of the Fund, an entity must be (i) a "Participating Party" (i.e., a broker- dealer or other participant in the clearing process through the Continuous Net Settlement System of the NSCC (the "Clearing Process")), a clearing agency that is registered with the SEC; or (ii) a DTC Participant (see "Book Entry Only System"). In addition, each Participating Party or DTC Participant (each, an "Authorized Participant") must execute a Participant Agreement that has been agreed to by the Distributor, and that has been accepted by the Transfer Agent, with respect to purchases and redemptions of Creation Units. Each Authorized Participant will agree, pursuant to the terms of a Participant Agreement, on behalf of itself or any investor on whose behalf it will act, to certain conditions, including that it will pay to the Trust, an amount of cash sufficient to pay the Cash Component together with the creation transaction fee (described below), if applicable, and any other applicable fees and taxes.

All orders to purchase Fund Shares directly from the Fund must be placed for one or more Creation Units and in the manner and by the time set forth in the Participant Agreement and/or applicable order form. The order cut-off time for the Fund for orders to purchase Creation Units is expected to be 2:00 p.m. Eastern Time which time may be modified by the Fund from time-to-time by amendment to the Participant Agreement and/or applicable order form. In the case of custom orders, the order must be received by the Transfer Agent no later than 2:30 p.m. Eastern Time or such earlier time as may be designated by the Fund and disclosed to Authorized Participants. The date on which an order to purchase Creation Units (or an order to redeem Creation Units, as set forth below) is received and accepted is referred to as the "Order Placement Date."

An Authorized Participant may require an investor to make certain representations or enter into agreements with respect to the order (e.g., to provide for payments of cash, when required). Investors should be aware that their particular broker may not have executed a Participant Agreement and that, therefore, orders to purchase Fund Shares directly from the Fund in Creation Units have to be placed by the investor's broker through an Authorized Participant that has executed a Participant Agreement. In such cases there may be additional charges to such investor. At any given time, there may be only a limited number of broker-dealers that have executed a Participant Agreement and only a small number of such Authorized Participants may have international capabilities.

On days when the Exchange closes earlier than normal, the Fund may require orders to create Creation Units to be placed earlier in the day. In addition, if a market or markets on which the Fund's investments are primarily traded is closed, the Fund will also generally not accept orders on such day(s). Orders must be transmitted by an Authorized Participant by telephone or other transmission method acceptable to the Transfer Agent pursuant to procedures set forth in the Participant Agreement and in accordance with the applicable order form. On behalf of the Fund, the Transfer Agent will notify the Custodian of such order. The Custodian will then provide such information to the appropriate local sub-custodian(s). Those placing orders through an Authorized Participant should allow sufficient time to permit proper submission of the purchase order to the Transfer Agent by the cut-off time on such Business Day. Economic or market disruptions or changes, or telephone or other communication failures may impede the ability to reach the Transfer Agent or an Authorized Participant.

Fund Deposits must be delivered by an Authorized Participant through the Federal Reserve System (for cash) or through DTC (for corporate securities), through a sub-custody agent (for foreign securities) and/or through such other arrangements allowed by the Trust or its agents. With respect to foreign Deposit Securities, the Custodian shall cause the sub-custodian of the Fund to maintain an account into which the Authorized Participant shall deliver, on behalf of itself or the party on whose behalf it is acting, such Deposit Securities (or Deposit Cash for all or a part of such securities, as permitted or required), with any appropriate adjustments as advised by the Trust. Foreign Deposit Securities must be delivered to an account maintained at the applicable local sub-custodian. The Fund Deposit transfer must be ordered by the Authorized Participant in a timely fashion so as to ensure the delivery of the requisite number of Deposit Securities or Deposit Cash, as applicable, to the account of the applicable Fund or its agents by no later than 12:00 p.m. Eastern Time (or such other time as specified by the Trust) on the Settlement Date. If the Fund or its agents do not receive all of the Deposit Securities, or the required Deposit Cash in lieu thereof, by such time, then the order may be deemed rejected and the Authorized Participant shall be liable to the Fund for losses, if any, resulting therefrom. The "Settlement Date" for the Fund is generally the second Business Day after the Order Placement Date. All questions as to the number of Deposit Securities or Deposit Cash to be delivered, as applicable, and the validity, form and eligibility (including time of receipt) for the deposit of any tendered securities or cash, as applicable, will be determined by the Trust, whose determination shall be final and binding. The amount of cash represented by the Cash Component must be transferred directly to the Custodian through the Federal Reserve Bank wire transfer system in a timely manner so as to be received by the Custodian no later than the Settlement Date. If the Cash Component and the Deposit Securities or Deposit Cash, as applicable, are not received by the Custodian in a timely manner by the Settlement Date, the creation order may be cancelled. Upon written notice to the Transfer Agent, such canceled order may be resubmitted the following Business Day using the Fund Deposit as newly constituted to reflect the then current NAV of the applicable Fund.

The order shall be deemed to be received on the Business Day on which the order is placed provided that the order is placed in proper form prior to the applicable cut-off time and the federal funds in the appropriate amount are deposited by 2:00 p.m. or 3:00 p.m., Eastern Time (as set forth on the applicable order form), with the Custodian on the Settlement Date. If the order is not placed in proper form as required, or federal funds in the appropriate amount are not received by 2:00 p.m. or 3:00 p.m., Eastern Time (as set forth on the applicable order form) on the Settlement Date, then the order may be deemed to be rejected and the Authorized Participant shall be liable to the Fund for losses, if any, resulting therefrom. A creation request is considered to be in "proper form" if all procedures set forth in the Participant Agreement, order form and this SAI are properly followed.

Issuance of a Creation Unit

Except as provided in this SAI, Creation Units will not be issued until the transfer of good title to the Trust of the Deposit Securities or payment of Deposit Cash, as applicable, and the payment of the Cash Component have been completed. When the sub-custodian has confirmed to the Custodian that the required Deposit Securities (or the cash value thereof) have been delivered to the account of the relevant sub-custodian or sub-custodians, the Transfer Agent and the Adviser shall be notified of such delivery, and the Trust will issue and cause the delivery of the Creation Units. The delivery of Creation Units so created generally will occur no later than the second Business Day following the day on which the purchase order is deemed received by the Transfer Agent. The Authorized Participant shall be liable to the applicable Fund for losses, if any, resulting from unsettled orders.

Creation Units may be purchased in advance of receipt by the Trust of all or a portion of the applicable Deposit Securities as described below. In these circumstances, the initial deposit will have a value greater than the NAV of Fund Shares on the date the order is placed in proper form since, in addition to available Deposit Securities, cash must be deposited in an amount equal to the sum of (i) the Cash Component, plus (ii) an additional amount of cash equal to up to 115% of the market value of the undelivered Deposit Securities (the "Additional Cash Deposit"), which shall be maintained in a separate non-interest bearing collateral account. The Authorized Participant must deposit with the Custodian the Additional Cash Deposit, as applicable, by 12:00 p.m. Eastern Time (or such other time as specified by the Trust) on the Settlement Date. If the Fund or its agents do not receive the Additional Cash Deposit in the appropriate amount, by such time, then the order may be deemed rejected and the Authorized Participant shall be liable to the Fund for losses, if any, resulting therefrom. An additional amount of cash shall be required to be deposited with the Trust, pending delivery of the missing Deposit Securities to the extent necessary to maintain the Additional Cash Deposit with the Trust in an amount at least equal to the applicable percentage, as set forth in the Participant Agreement, of the daily market value of the missing Deposit Securities. The Participant Agreement will permit the Trust to buy the missing Deposit Securities at any time. Authorized Participants will be liable to the Trust for the costs incurred by the Trust in connection with any such purchases. These costs will be deemed to include the amount by which the actual purchase price of the Deposit Securities exceeds the value of such Deposit Securities on the day the purchase order was deemed received by the Transfer Agent plus the brokerage and related transaction costs associated with such purchases.

The Trust will return any unused portion of the Additional Cash Deposit once all of the missing Deposit Securities have been properly received by the Custodian or purchased by the Trust and deposited into the Trust. In addition, a transaction fee, as described below under "Creation Transaction Fee," may be charged. The delivery of Creation Units so created generally will occur no later than the Settlement Date.

Acceptance of Orders of Creation Units

The Trust reserves the right to reject an order for Creation Units transmitted to it by the Transfer Agent with respect to the Fund including, without limitation, if (a) the order is not in proper form; (b) the Deposit Securities or Deposit Cash, as applicable, delivered by the Participant are not as disseminated through the facilities of the NSCC for that date by the Custodian; (c) the investor(s), upon obtaining Fund Shares ordered, would own 80% or more of the currently outstanding Fund Shares; (d) the acceptance of the Fund Deposit would, in the opinion of counsel, be unlawful; (e) the acceptance or receipt of the order for a Creation Unit would, in the opinion of counsel to the Trust, be unlawful; or (f) in the event that circumstances outside the control of the Trust, the Custodian, the Transfer Agent and/or the Adviser make it for all practical purposes not feasible to process orders for Creation Units.

Examples of such circumstances include acts of God or public service or utility problems such as fires, floods, extreme weather conditions and power outages resulting in telephone, telecopy and computer failures; market conditions or activities causing trading halts; systems failures involving computer or other information systems affecting the Trust, the Distributor, the Custodian, a sub-custodian, the Transfer Agent, DTC, NSCC, Federal Reserve System, or any other participant in the creation process, and other extraordinary events. The Transfer Agent shall notify a prospective creator of a Creation Unit and/or the Authorized Participant acting on behalf of the creator of a Creation Unit of its rejection of the order of such person. The Trust, the Transfer Agent, the Custodian, any sub-custodian and the Distributor are under no duty, however, to give notification of any defects or irregularities in the delivery of Fund Deposits nor shall either of them incur any liability for the failure to give any such notification. The Trust, the Transfer Agent, the Custodian and the Distributor shall not be liable for the rejection of any purchase order for Creation Units.

All questions as to the number of Fund Shares of each security in the Deposit Securities and the validity, form, eligibility and acceptance for deposit of any securities to be delivered shall be determined by the Trust, and the Trust's determination shall be final and binding.

Creation Transaction Fee

A fixed purchase (i.e., creation) transaction fee, payable to the Fund's custodian, may be imposed for the transfer and other transaction costs associated with the purchase of Creation Units ("Creation Order Costs"). The standard fixed creation transaction fee for the Fund is $250 for in-kind Creation Units or $100 for cash Creation Units, or such other amount as agreed to in writing between the parties, regardless of the number of Creation Units created in the transaction. The Fund may adjust the standard fixed creation transaction fee from time to time. The fixed creation fee may be waived on certain orders if the Fund's custodian has determined to waive some or all of the Creation Order Costs associated with the order or another party, such as the Adviser, has agreed to pay such fee.

In addition, a variable fee, payable to the Fund, of up to a maximum of 2% of the value of the Creation Units subject to the transaction may be imposed for cash purchases, non-standard orders, or partial cash purchases of Creation Units. The variable charge is primarily designed to cover additional costs (e.g., brokerage, taxes) involved with buying the securities with cash. The Fund may determine to not charge a variable fee on certain orders when the Adviser has determined that doing so is in the best interests of Fund shareholders, e.g., for creation orders that facilitate the rebalance of the Fund's portfolio in a more tax efficient manner than could be achieved without such order. Investors who use the services of a broker or other such intermediary may be charged a fee for such services. Investors are responsible for the fixed costs of transferring the Fund Securities from the Trust to their account or on their order.

Risks of Purchasing Creation Units

There are certain legal risks unique to investors purchasing Creation Units directly from the Fund. Because Fund Shares may be issued on an ongoing basis, a "distribution" of Fund Shares could be occurring at any time. Certain activities that a shareholder performs as a dealer could, depending on the circumstances, result in the shareholder being deemed a participant in the distribution in a manner that could render the shareholder a statutory underwriter and subject to the prospectus delivery and liability provisions of the Securities Act. For example, a shareholder could be deemed a statutory underwriter if it purchases Creation Units from the Fund, breaks them down into the constituent Fund Shares, and sells those Fund Shares directly to customers, or if a shareholder chooses to couple the creation of a supply of new Fund Shares with an active selling effort involving solicitation of secondary-market demand for Fund Shares. Whether a person is an underwriter depends upon all of the facts and circumstances pertaining to that person's activities, and the examples mentioned here should not be considered a complete description of all the activities that could cause you to be deemed an underwriter.

Dealers who are not "underwriters" but are participating in a distribution (as opposed to engaging in ordinary secondary-market transactions), and thus dealing with Fund Shares as part of an "unsold allotment" within the meaning of Section 4(a)(3)(C) of the Securities Act, will be unable to take advantage of the prospectus delivery exemption provided by Section 4(a)(3) of the Securities Act.

Redemptions

Fund Shares may be redeemed only in Creation Units at their NAV next determined after receipt of a redemption request in proper form by the Fund through the Transfer Agent and only on a Business Day. Except upon liquidation of the Fund, the Trust will not redeem Fund Shares in amounts less than Creation Units. Investors must accumulate enough Fund Shares in the secondary market to constitute a Creation Unit to have such Fund Shares redeemed by the Trust. There can be no assurance, however, that there will be sufficient liquidity in the public trading market at any time to permit assembly of a Creation Unit. Investors should expect to incur brokerage and other costs in connection with assembling a sufficient number of Fund Shares to constitute a redeemable Creation Unit.

With respect to the Fund, the Custodian, through the NSCC, makes available prior to the opening of business on the Exchange (currently 9:30 a.m., Eastern Time) on each Business Day, the list of the names and Share quantities of the Fund's portfolio securities that will be applicable (subject to possible amendment or correction) to redemption requests received in proper form (as defined below) on that day ("Fund Securities"). Fund Securities received on redemption may not be identical to Deposit Securities.

Redemption proceeds for a Creation Unit are paid either in-kind or in cash, or combination thereof, as determined by the Trust. With respect to in-kind redemptions of the Fund, redemption proceeds for a Creation Unit will consist of Fund Securities - as announced by the Custodian on the Business Day of the request for redemption received in proper form plus cash in an amount equal to the difference between the NAV of Fund Shares being redeemed, as next determined after a receipt of a request in proper form, and the value of the Fund Securities (the "Cash Redemption Amount"), less a fixed redemption transaction fee, as applicable, as set forth below. In the event that the Fund Securities have a value greater than the NAV of Fund Shares, a compensating cash payment equal to the differential is required to be made by or through an Authorized Participant by the redeeming shareholder. Notwithstanding the foregoing, at the Trust's discretion, an Authorized Participant may receive the corresponding cash value of the securities in lieu of the in-kind securities value representing one or more Fund Securities.

Redemption Transaction Fee

A fixed redemption transaction fee, payable to the Fund's custodian, may be imposed for the transfer and other transaction costs associated with the redemption of Creation Units ("Redemption Order Costs"). The standard fixed redemption transaction fee for the Fund is $250 for in-kind Creation Units or $100 for cash Creation Units, or such other amount as agreed to in writing between the parties, regardless of the number of Creation Units redeemed in the transaction. The Fund may adjust the redemption transaction fee from time to time. The fixed redemption fee may be waived on certain orders if the Fund's custodian has determined to waive some or all of the Redemption Order Costs associated with the order or another party, such as the Adviser, has agreed to pay such fee.

In addition, a variable fee, payable to the Fund, of up to a maximum of 2% of the value of the Creation Units subject to the transaction may be imposed for cash redemptions, non-standard orders, or partial cash redemptions (when cash redemptions are available) of Creation Units. The variable charge is primarily designed to cover additional costs (e.g., brokerage, taxes) involved with selling portfolio securities to satisfy a cash redemption. The Fund may determine to not charge a variable fee on certain orders when the Adviser has determined that doing so is in the best interests of Fund shareholders, e.g., for redemption orders that facilitate the rebalance of the Fund's portfolio in a more tax efficient manner than could be achieved without such order.

Investors who use the services of a broker or other such intermediary may be charged a fee for such services. Investors are responsible for the fixed costs of transferring the Fund Securities from the Trust to their account or on their order.

Procedures for Redemption of Creation Units

Orders to redeem Creation Units must be submitted in proper form to the Transfer Agent prior to 4:00 p.m. Eastern Time. A redemption request is considered to be in "proper form" if (i) an Authorized Participant has transferred or caused to be transferred to the Trust's Transfer Agent the Creation Unit(s) being redeemed through the book-entry system of DTC so as to be effective by the time as set forth in the Participant Agreement and (ii) a request in form satisfactory to the Trust is received by the Transfer Agent from the Authorized Participant on behalf of itself or another redeeming investor within the time periods specified in the Participant Agreement. If the Transfer Agent does not receive the investor's Fund Shares through DTC's facilities by the times and pursuant to the other terms and conditions set forth in the Participant Agreement, the redemption request shall be rejected.

The Authorized Participant must transmit the request for redemption, in the form required by the Trust, to the Transfer Agent in accordance with procedures set forth in the Authorized Participant Agreement. Investors should be aware that their particular broker may not have executed an Authorized Participant Agreement, and that, therefore, requests to redeem Creation Units may have to be placed by the investor's broker through an Authorized Participant who has executed an Authorized Participant Agreement. Investors making a redemption request should be aware that such request must be in the form specified by such Authorized Participant. Investors making a request to redeem Creation Units should allow sufficient time to permit proper submission of the request by an Authorized Participant and transfer of the Fund Shares to the Trust's Transfer Agent; such investors should allow for the additional time that may be required to effect redemptions through their banks, brokers or other financial intermediaries if such intermediaries are not Authorized Participants.

Additional Redemption Procedures

In connection with taking delivery of Fund Shares of Fund Securities upon redemption of Creation Units, a redeeming shareholder or Authorized Participant acting on behalf of such shareholder must maintain appropriate custody arrangements with a qualified broker-dealer, bank or other custody providers in each jurisdiction in which any of the Fund Securities are customarily traded, to which account such Fund Securities will be delivered. Deliveries of redemption proceeds generally will be made within two business days of the trade date.

The Trust may in its discretion exercise its option to redeem such Fund Shares in cash, and the redeeming investor will be required to receive its redemption proceeds in cash. In addition, an investor may request a redemption in cash that the Fund may, in its sole discretion, permit. In either case, the investor will receive a cash payment equal to the NAV of its Fund Shares based on the NAV of Fund Shares next determined after the redemption request is received in proper form (minus a redemption transaction fee, if applicable, and additional charge for requested cash redemptions specified above, to offset the Trust's brokerage and other transaction costs associated with the disposition of Fund Securities). The Fund may also, in its sole discretion, upon request of a shareholder, provide such redeemer a portfolio of securities that differs from the exact composition of the Fund Securities but does not differ in NAV.

Redemptions of Fund Shares for Fund Securities will be subject to compliance with applicable federal and state securities laws and the Fund (whether or not it otherwise permits cash redemptions) reserve the right to redeem Creation Units for cash to the extent that the Trust could not lawfully deliver specific Fund Securities upon redemptions or could not do so without first registering the Fund Securities under such laws. An Authorized Participant or an investor for which it is acting subject to a legal restriction with respect to a particular security included in the Fund Securities applicable to the redemption of Creation Units may be paid an equivalent amount of cash. The Authorized Participant may request the redeeming investor of Fund Shares to complete an order form or to enter into agreements with respect to such matters as compensating cash payment. Further, an Authorized Participant that is not a "qualified institutional buyer," ("QIB") as such term is defined under Rule 144A of the Securities Act, will not be able to receive Fund Securities that are restricted securities eligible for resale under Rule 144A. An Authorized Participant may be required by the Trust to provide a written confirmation with respect to QIB status to receive Fund Securities.

The right of redemption may be suspended or the date of payment postponed with respect to the Fund (1) for any period during which the Exchange is closed (other than customary weekend and holiday closings); (2) for any period during which trading on the Exchange is suspended or restricted; (3) for any period during which an emergency exists as a result of which disposal of Fund Shares or determination of the NAV of Fund Shares is not reasonably practicable; or (4) in such other circumstance as is permitted by the SEC.

For every occurrence of one or more intervening holidays in the applicable foreign market that are not holidays observed in the U.S. equity market, the redemption settlement cycle will be extended by the number of such intervening holidays. In addition to holidays, other unforeseeable closings in a foreign market due to emergencies may also prevent the Trust from delivering securities within normal settlement period.

The securities delivery cycles currently practicable for transferring portfolio securities to redeeming investors, coupled with foreign market holiday schedules, will require, in certain circumstances, a delivery process longer than seven calendar days for the Fund. Although certain holidays may occur on different dates in subsequent years, the number of days required to deliver redemption proceeds in any given year is not expected to exceed the maximum number of days listed below for the Fund. The proclamation of new holidays, the treatment by market participants of certain days as "informal holidays" (e.g., days on which no or limited securities transactions occur, as a result of substantially shortened trading hours), the elimination of existing holidays, or changes in local securities delivery practices, could affect the information set forth herein at some time in the future.

Custom Baskets

Creation and Redemption baskets may differ and the Fund may accept "custom baskets." A custom basket may include any of the following: (i) a basket that is composed of a non-representative selection of the Fund's portfolio holdings; (ii) a representative basket that is different from the initial basket used in transactions on the same business day; or (iii) a basket that contains bespoke cash substitutions for a single Authorized Participant. The Fund has adopted policies and procedures that govern the construction and acceptance of baskets, including heightened requirements for certain types of custom baskets. Such policies and procedures provide the parameters for the construction and acceptance of custom baskets that are in the best interests of the Fund and their shareholders, establish processes for revisions to, or deviations from, such parameters, and specify the titles and roles of the employees of the Adviser who are required to review each custom basket for compliance with those parameters. In addition, when constructing custom baskets for redemptions, the tax efficiency of the Fund may be taken into account. The policies and procedures distinguish among different types of custom baskets that may be used and impose different requirements for different types of custom baskets in order to seek to mitigate against potential risks of conflicts and/or overreaching by an Authorized Participant. The Adviser has established a governance process to oversee basket compliance for the Fund, as set forth in the Fund's policies and procedures.

DETERMINATION OF NET ASSET VALUE

The NAV of Fund Shares is determined at the close of regular trading on the New York Stock Exchange (normally 4:00 p.m. Eastern Time) on each day the NYSE is open. NAV is computed by determining the aggregate market value of all assets of the applicable Fund, less its liabilities, divided by the total number of Fund Shares outstanding ((assets-liabilities)/number of Fund Shares = NAV). The NYSE is closed on weekends and New Year's Day, Martin Luther King, Jr. Day, Presidents' Day, Good Friday, Memorial Day, Juneteenth National Independence Day, Independence Day, Labor Day, Thanksgiving Day and Christmas Day. The NAV takes into account the expenses and fees of the Fund, including management, administration, and distribution fees, which are accrued daily. The determination of NAV for the Fund for a particular day is applicable to all applications for the purchase of Fund Shares, as well as all requests for the redemption of Fund Shares, received by the Fund (or an authorized broker or agent, or its authorized designee) before the close of trading on the NYSE on that day.

Generally, securities traded or dealt in upon one or more securities exchanges (whether domestic or foreign) for which market quotations are readily available and not subject to restrictions against resale shall be valued at the last quoted sales price on the primary exchange or, in the absence of a sale on the primary exchange, at the mean between the current bid and ask prices on such exchange. Securities primarily traded in the National Association of Securities Dealers' Automated Quotation System ("NASDAQ") National Market System for which market quotations are readily available shall be valued using the NASDAQ Official Closing Price. Securities that are not traded or dealt in any securities exchange (whether domestic or foreign) and for which over-the-counter market quotations are readily available generally shall be valued at the last sale price or, in the absence of a sale, at the mean between the current bid and ask price on such over-the-counter market. Debt securities not traded on an exchange may be valued at prices supplied by a pricing agent(s) based on broker or dealer supplied valuations or matrix pricing, a method of valuing securities by reference to the value of other securities with similar characteristics, such as rating, interest rate and maturity. Futures, swaps and options contracts listed for trading on a futures or options exchange or board of trade for which market quotations are generally available are valued at the last quoted sale price, or, in the absence of a sale, at the mean of the last bid and ask price. Total return swaps on exchange-listed securities are valued at the last quoted sale price, or, in the absence of a sale, at the mean of the last bid and ask price.

If market quotations are not readily available, securities or other assets will be valued at their fair market value as determined in good faith by the Adviser in accordance with procedures approved by the Board and evaluated by the Board as to the reliability of the fair value method used. In these cases, the Fund's NAV will reflect certain portfolio securities' fair value rather than their market price. Fair value pricing involves subjective judgments, and it is possible that the fair value determined for a security or other asset may be materially different than the value that could be realized upon the sale of that security or other asset. The fair value prices can differ from market prices when they become available or when a price becomes available. The Board has delegated execution of these procedures to Calamos Advisors as "valuation designee" for the Fund. Calamos Advisors may also enlist third party consultants such as an audit firm or financial officer of a security issuer on an as-needed basis to assist in determining a security-specific fair value. Calamos Advisors reviews and ratifies the execution of this process and the resultant fair value prices at least quarterly to assure the process produces reliable results.

The Fund may use independent pricing services to assist in calculating the value of the Fund's securities or other assets. In addition, market prices for foreign securities are not determined at the same time of day as the NAV for the Fund. Because the Fund may invest in securities primarily listed on foreign exchanges, and these exchanges may trade on weekends or other days when the Fund does not price its Fund Shares, the value of some of the Fund's portfolio securities may change on days when you may not be able to buy or sell Fund Shares.

In computing the NAV, the Fund values foreign securities held by the Fund at the latest closing price on the exchange in which they are traded immediately prior to closing of the NYSE. Prices of foreign securities quoted in foreign currencies are translated into U.S. dollars at current rates. If events materially affecting the value of a security in the Fund's portfolio, particularly foreign securities, occur after the close of trading on a foreign market but before the Fund prices its shares, the security will be valued at fair value. For example, if trading in a portfolio security is halted and does not resume before the Fund calculates its NAV, the Adviser may need to price the security using the Fund's fair value pricing guidelines. Without a fair value price, short-term traders could take advantage of the arbitrage opportunity and dilute the NAV of long-term investors. Fair valuation of the Fund's portfolio securities can serve to reduce arbitrage opportunities available to short-term traders, but there is no assurance that fair value pricing policies will prevent dilution of the Fund's NAVs by short term traders. The determination of fair value involves subjective judgments. As a result, using fair value to price a security may result in a price materially different from the prices used by other funds to determine NAV, or from the price that may be realized upon the actual sale of the security.

With respect to any portion of the Fund's assets that are invested in one or more open-end management investment companies registered under the 1940 Act, the Fund's NAV is calculated based upon the NAVs of those open-end management investment companies, and the prospectuses for these companies explain the circumstances under which those companies will use fair value pricing and the effects of using fair value pricing.

DIVIDENDS AND DISTRIBUTIONS

The following information supplements and should be read in conjunction with the section in the Prospectus entitled "DIVIDENDS, OTHER DISTRIBUTIONS AND TAXES."

General Policies

The Fund expects to declare and distribute all of its net investment income and capital gains, if any, to shareholders as dividends at least annually. The Fund may distribute such investment income dividends and capital gains more frequently, if necessary, in order to reduce or eliminate federal excise or income taxes on the Fund.

Dividend Distributions

Dividends and other distributions on Fund Shares are distributed, as described below, on a pro rata basis to Beneficial Owners of such Fund Shares. Dividend payments are made through DTC Participants and Indirect Participants to Beneficial Owners then of record with proceeds received from the Trust.

Dividend Reinvestment Service

The Trust will not make the DTC book-entry dividend reinvestment service available for use by Beneficial Owners for reinvestment of their cash proceeds, but certain individual broker-dealers may make available the DTC book-entry Dividend Reinvestment Service for use by Beneficial Owners of the Fund through DTC Participants for reinvestment of their dividend distributions. Investors should contact their brokers to ascertain the availability and description of these services. Beneficial Owners should be aware that each broker may require investors to adhere to specific procedures and timetables in order to participate in the dividend reinvestment service and investors should ascertain from their brokers such necessary details. If this service is available and used, dividend distributions of both investment income and realized gains will be automatically reinvested in additional whole Fund Shares issued by the Trust of the same Fund at NAV per Share. Distributions reinvested in additional Fund Shares of the Fund will nevertheless be taxable to Beneficial Owners acquiring such additional Fund Shares to the same extent as if such distributions had been received in cash.

TAXATION

This section summarizes some of the main U.S. federal income tax consequences of owning shares of the Fund. This section is current as of the date of this SAI. Tax laws and interpretations change frequently, and these summaries do not describe all of the tax consequences to all taxpayers. For example, these summaries generally do not describe your situation if you are a corporation, a non-U.S. person, a broker-dealer, or other investor with special circumstances. In addition, this section does not describe your state, local or foreign tax consequences.

This federal income tax summary is based in part on the advice of counsel to the Fund. The Internal Revenue Service could disagree with any conclusions set forth in this section. In addition, our counsel was not asked to review, and has not reached a conclusion with respect to the federal income tax treatment of the assets to be deposited in the Fund. This may not be sufficient for prospective investors to use for the purpose of avoiding penalties under federal tax law.

As with any investment, prospective investors should seek advice based on their individual circumstances from their own tax advisor.

The Fund intends to qualify annually and to elect to be treated as a regulated investment company under the Code. The Fund's ability to qualify as a regulated investment company depends upon the Underlying ETFs themselves qualifying as regulated investment companies.

To qualify for the favorable U.S. federal income tax treatment generally accorded to regulated investment companies, the Fund must, among other things, (i) derive in each taxable year at least 90% of its gross income from dividends, interest, payments with respect to securities loans and gains from the sale or other disposition of stock, securities or foreign currencies or other income (including but not limited to gains from options, futures, or forward contracts) derived with respect to its business of investing in such stock, securities or currencies, or net income derived from interests in certain publicly traded partnerships; (ii) diversify its holdings so that, at the end of each quarter of the taxable year, (a) at least 50% of the market value of the Fund's assets is represented by cash and cash items (including receivables), U.S. government securities, the securities of other regulated investment companies and other securities, with such other securities of any one issuer generally limited for the purposes of this calculation to an amount not greater than 5% of the value of the Fund's total assets and not greater than 10% of the outstanding voting securities of such issuer, and (b) not more than 25% of the value of its total assets is invested in the securities (other than U.S. government securities or the securities of other regulated investment companies) of any one issuer, or two or more issuers which the Fund controls and which are engaged in the same, similar or related trades or businesses, or the securities of one or more of certain publicly traded partnerships; and (iii) distribute at least 90% of its investment company taxable income (which includes, among other items, dividends, interest and net short-term capital gains in excess of net long-term capital losses) and at least 90% of its net tax-exempt interest income each taxable year. There are certain exceptions for failure to qualify if the failure is for reasonable cause or is de minimis, and certain corrective action is taken and certain tax payments are made by the Fund.

For purposes of the diversification tests, the identification of the issuer (or, in some cases, issuers) of a particular investment can depend on the terms and conditions of such investment. Because there is no published Internal Revenue Service guidance or case law on how to determine the "issuer" of various derivatives that the Underlying ETFs may enter into, there is a risk that the Underlying ETFs will not meet the Code's diversification requirements and will not qualify, or will be disqualified, as regulated investment companies. If the Underlying ETFs failed to qualify as regulated investment companies, the Fund also would not meet the Code's diversification requirements and would not qualify, or would be disqualified, as a regulated investment company. See discussion under heading "Tax Risk."

As a regulated investment company, the Fund generally will not be subject to U.S. federal income tax on its investment company taxable income (as that term is defined in the Code, but without regard to the deduction for dividends paid) and net capital gain (the excess of net long-term capital gain over net short-term capital loss), if any, that it distributes to shareholders. The Fund intends to distribute to its shareholders, at least annually, substantially all of its investment company taxable income and net capital gain. If the Fund retains any net capital gain or investment company taxable income, it will generally be subject to federal income tax at regular corporate rates on the amount retained. However, if the Fund retains any net capital gain, the Fund may report the retained amount as undistributed capital gains to shareholders who, if subject to U.S. federal income tax on long-term capital gains, (i) will be required to include in income as long-term capital gain their proportionate share of such undistributed amount, and (ii) will be entitled to credit their proportionate share of the federal income tax paid by the Fund on the undistributed amount against their U.S. federal income tax liabilities, if any, and to claim refunds to the extent the credit exceeds such liabilities. If the Fund makes this designation, the tax basis of shares owned by a shareholder of the Fund will, for U.S. federal income tax purposes, generally be increased by the difference between the amount of undistributed net capital gain included in the shareholder's gross income and the federal income tax deemed paid by the shareholder.

In addition, amounts not distributed on a timely basis in accordance with a calendar year distribution requirement are subject to a nondeductible 4% excise tax unless, generally, the Fund distributes during each calendar year an amount equal to the sum of (1) at least 98% of its ordinary income (not taking into account any capital gains or losses) for the calendar year, (2) at least 98.2% of its capital gains in excess of its capital losses (adjusted for certain ordinary losses) for the one-year period ending October 31 of the calendar year, and (3) any ordinary income and capital gains for previous years that were not distributed during those years. In order to prevent application of the excise tax, the Fund intends to make its distributions in accordance with the calendar year distribution requirement. A distribution will be treated as paid on December 31 of the current calendar year if it is declared by the Fund in October, November or December with a record date in such a month and paid by the Fund during January of the following calendar year. Such distributions will be taxable to shareholders in the calendar year in which the distributions are declared, rather than the calendar year in which the distributions are received.

Subject to certain reasonable cause and de minimis exceptions, if the Fund fails to qualify as a regulated investment company or failed to satisfy the 90% distribution requirement in any taxable year, the Fund would be taxed as an ordinary corporation on its taxable income (even if such income were distributed to its shareholders), and all distributions out of earnings and profits would be taxed to shareholders as ordinary income.

Distributions

Dividends paid out of the Fund's investment company taxable income are generally taxable to a shareholder as ordinary income to the extent of the Fund's earnings and profits, whether paid in cash or reinvested in additional shares. However, certain ordinary income distributions paid by the Fund may be taxed at long-term capital gains tax rates. In particular, dividends received by an individual shareholder from a regulated investment company such as the Fund may be treated as "qualified dividend income" that is eligible to be taxed at the same rates that apply to net capital gain, provided that certain holding period requirements are satisfied by both the Fund and shareholder and provided the dividends are attributable to qualifying dividends received by the Fund itself.

The Fund will provide notice to its shareholders of the amount of any distributions that may be taken into account as a dividend, which is eligible for the long-term capital gains tax rates. If the Fund receives dividends from an Underlying ETF and the Underlying ETF reports such dividends as qualified dividend income, then the Fund is permitted in turn to report a portion of its distributions as qualified dividend income, provided the Fund meets holding period and other requirements with respect to shares of the Underlying ETF. The Underlying ETFs and therefore the Fund do not anticipate that they will have qualified dividend income.

Income from the Fund may also be subject to a 3.8% "Medicare tax." This tax generally applies to net investment income if the taxpayer's adjusted gross income exceeds certain threshold amounts, which are $250,000 in the case of married couples filing joint returns and $200,000 in the case of single individuals.

A portion of dividends from the Fund also may be eligible for the dividends-received deduction allowed to corporations, provided certain holding period and other requirements are satisfied. The eligible portion is not permitted to exceed the aggregate dividends the Fund receives from U.S. corporations. Funds with higher concentrations of securities other than stock of U.S. corporations are generally not expected to designate a significant portion of their distributions as qualifying for the dividends-received deduction. If the Fund receives dividends from an Underlying ETF and the Underlying ETF reports such dividends as eligible for the dividends-received deduction, then the Fund is permitted in turn to report a portion of its distributions as eligible for the dividends-received deduction, provided the Fund meets holding period and other requirements with respect to shares of the Underlying ETF. The Underlying ETFs and therefore the Fund do not anticipate that they will make distributions eligible for the dividends-received deduction.

Distributions of net capital gain (the excess of net long-term capital gain over net short-term capital loss), if any, properly reported as capital gain dividends are taxable to a shareholder as long-term capital gains, regardless of how long the shareholder has held Fund Shares. The Internal Revenue Service and the Department of the Treasury have issued regulations that impose special rules in respect of capital gain dividends received through partnership interests constituting "applicable partnership interests" under Section 1061 of the Code. Shareholders receiving distributions in the form of additional Fund Shares, rather than cash, generally will have a tax basis in each such Fund Share equal to the value of a share of the Fund on the reinvestment date. A distribution of an amount in excess of the Fund's current and accumulated earnings and profits will be treated by a shareholder as a return of capital which is applied against and reduces the shareholder's basis in his or her Fund Shares. To the extent that the amount of any such distribution exceeds the shareholder's basis in his or her Fund Shares, the excess will be treated by the shareholder as gain from a sale or exchange of the Fund Shares.

Shareholders will be notified annually as to the U.S. federal income tax status of distributions, and shareholders receiving distributions in the form of additional Fund Shares will receive a report as to the value of those Fund Shares.

Sale or Exchange of Fund Shares

Upon the sale or other disposition of Fund Shares, which a shareholder holds as a capital asset, such a shareholder may realize a capital gain or loss, which will be long-term or short-term, depending upon the shareholder's holding period for the Fund Shares. Generally, a shareholder's gain or loss will be a long-term gain or loss if the Fund Shares have been held for more than one year.

Any loss realized on a sale or exchange will be disallowed to the extent that Fund Shares disposed of are replaced (including through reinvestment of dividends) within a period of 61 days beginning 30 days before and ending 30 days after disposition of Fund Shares or to the extent that the shareholder, during such period, acquires or enters into an option or contract to acquire substantially identical stock or securities. In such a case, the basis of the Fund Shares acquired will be adjusted to reflect the disallowed loss. Any loss realized by a shareholder on a disposition of Fund Shares held by the shareholder for six months or less will be treated as a long-term capital loss to the extent of any distributions of long-term capital gain received by the shareholder with respect to such Fund Shares.

Taxes on Purchase and Redemption of Creation Units

If a shareholder exchanges securities for Creation Units, the shareholder will generally recognize a gain or a loss. The gain or loss will be equal to the difference between the market value of the Creation Units at the time plus (or minus) any Cash Component received (or paid) and the shareholder's aggregate basis in the securities surrendered. If a shareholder exchanges Creation Units for securities, then the shareholder will generally recognize a gain or loss equal to the difference between the aggregate market value of the securities received, plus (or minus) any Cash Redemption Amount received (or paid), and such shareholder's basis in the Creation Units. The Internal Revenue Service, however, may assert that a loss realized upon an exchange of securities for Creation Units or Creation Units for securities cannot be deducted currently under the rules governing "wash sales," or on the basis that there has been no significant change in economic position. In addition, when a regulated investment company redeems a shareholder in kind, the regulated investment company generally is not required to recognize taxable gains in respect of the portfolio securities it distributes to the redeeming shareholder. However, the Fund may be required to recognize taxable gain on the distribution of certain securities, and the Internal Revenue Service may assert that the Fund must recognize taxable gain in respect of certain other securities that the Fund distributes to a shareholder in exchange for Creation Units, which may increase the amount of taxable gains that the Fund would otherwise be required to distribute in order to maintain its qualification as a regulated investment company and avoid the Fund-level tax.

Authorized Participants that are dealers may be subject to special tax rules and should consult their own tax advisors regarding the tax consequences of purchasing and redeeming Creation Units in their capacity as dealers.

Investment in Underlying ETFs

The Fund's investments in shares of the Underlying ETFs can cause the Fund to be required to distribute greater amounts of net investment income or net capital gain than the Fund would have distributed had it invested directly in the securities held by the Underlying ETF, rather than in shares of the Underlying ETF. Further, the amount or timing of distributions from the Fund qualifying for treatment as a particular character (e.g., long-term capital gain, eligibility for dividends-received deduction, etc.) will not necessarily be the same as it would have been had the Fund invested directly in the securities held by the Underlying ETF.

Because the Fund will invest all of its assets in shares of the Underlying ETFs, its distributable income and gains will normally consist entirely of distributions from the Underlying ETFs and gains and losses on the disposition of shares of the Underlying ETFs. To the extent that an Underlying ETF realizes net losses on its investments for a given taxable year, the Fund will not be able to benefit from those losses until and only to the extent that (i) the Underlying ETF realizes gains that it can reduce by those losses, or (ii) the Fund recognizes its share of those losses (so as to offset distributions or capital gains from other Underlying ETFs) when it disposes of shares of the Underlying ETF in a transaction qualifying for sale or exchange treatment. Moreover, even when the Fund does make such a disposition, a portion of its loss may be recognized as a long-term capital loss, which will not be treated as favorably for U.S. federal income tax purposes as a short-term capital loss or an ordinary deduction. In particular, the Fund will not be able to offset any capital losses from its dispositions of Underlying ETF shares against its ordinary income (including distributions deriving from net short-term capital gains realized by an Underlying ETF).

In addition, in certain circumstances, the "wash sale" rules under Section 1091 of the Code may apply to the Fund's sales of Underlying ETF shares that have generated losses. A wash sale occurs if shares of an Underlying ETF are sold by the Fund at a loss and the Fund acquires additional shares of that same Underlying ETF 30 days before or after the date of the sale. The wash-sale rules could defer losses in the Fund's hands on sales of Underlying ETF shares (to the extent such sales are wash sales) for extended (and, in certain cases, potentially indefinite) periods of time.

As a result of the foregoing rules, and certain other special rules, it is possible that the amounts of net investment income and net capital gain that the Fund will be required to distribute to shareholders will be greater than such amounts would have been had the Fund invested directly in the securities held by the Underlying ETFs, rather than investing in shares of the Underlying ETF. For similar reasons, the amount or timing of distributions from the Fund qualifying for treatment as a particular character (e.g., long-term capital gain, exempt interest, eligibility for dividends-received deduction, etc.) will not necessarily be the same as it would have been had the Fund invested directly in the securities held by the Underlying ETFs.

If the Fund was to own 20% or more of the voting interests of an Underlying ETF, subject to a safe harbor in respect of certain fund of funds arrangements, the Fund would be required to "look through" the Underlying ETF to its holdings and combine the appropriate percentage (as determined pursuant to the applicable Treasury Regulations) of the Underlying ETF's assets with the Fund's assets for purposes of satisfying the 25% diversification test described above.

Treatment of FLEX Options

The FLEX Options included in each Underlying ETF's portfolio are exchange-traded options. Under Section 1256 of the Code, certain types of exchange-traded options are treated as if they were sold (i.e., "marked to market") at the end of each year. The Underlying ETFs do not believe that the positions they hold in FLEX Options will be subject to Section 1256 or be marked to market, but the positions will be subject to the straddle rules. See discussion under heading "Options, Futures and Forward Contracts, and Swap Agreements or Derivatives."

Options, Futures and Forward Contracts, and Swap Agreements or Derivatives

In general, option premiums received by each Underlying ETF are not immediately included in the income of the Underlying ETF. Instead, the premiums are recognized when the option contract expires, the option is exercised by the holder, or the Underlying ETF transfers or otherwise terminates the option (e.g., through a closing transaction). If a call option written by an Underlying ETF is exercised and the Underlying ETF sells or delivers the underlying stock, the Underlying ETF generally will recognize capital gain or loss equal to (a) the sum of the strike price and the option premium received by the Underlying ETF minus (b) the Underlying ETF's basis in the stock. Such gain or loss generally will be short-term or long-term depending upon the holding period of the underlying stock. If securities are purchased by the Underlying ETF pursuant to the exercise of a put option written by it, the Underlying ETF generally will subtract the premium received for purposes of computing its cost basis in the securities purchased. Gain or loss arising in respect of a termination of an Underlying ETF's obligation under an option other than through the exercise of the option will be short-term gain or loss depending on whether the premium income received by the Underlying ETF is greater or less than the amount paid by the Underlying ETF (if any) in terminating the transaction. Thus, for example, if an option written by an Underlying ETF expires unexercised, the Underlying ETF generally will recognize short-term gain equal to the premium received.

The tax treatment of certain positions entered into by the Underlying ETFs (including options, futures contracts, forward contracts, foreign currency positions and swap agreements) may be governed by Section 1256 of the Code ("Section 1256 contracts"). Any gains or losses on Section 1256 contracts are generally considered 60% long-term and 40% short-term capital gains or losses ("60/40"), although certain foreign currency gains and losses from such contracts may be treated as ordinary in character. Also, Section 1256 contracts held by the Underlying ETFs at the end of each taxable year (and, for purposes of the 4% excise tax, on certain other dates as prescribed under the Code) are "marked to market" with the result that unrealized gains or losses are treated as though they were realized and the resulting gain or loss is treated as ordinary or 60/40 gain or loss, as applicable. The Underlying ETFs do not believe that the positions they hold in FLEX Options will be subject to Section 1256.

The Underlying ETF's options activities, including FLEX Options, may include transactions constituting straddles for U.S. federal income tax purposes, that is, that trigger the straddle rules contained primarily in Section 1092 of the Code. In some cases, the straddle rules also could apply in connection with swap agreements. Very generally, where applicable, Section 1092 requires (i) that losses be deferred on positions deemed to be offsetting positions with respect to "substantially similar or related property," to the extent of unrealized gain in the latter, and (ii) that the holding period of such a straddle position that has not already been held for the long-term holding period be terminated and begin anew once the position is no longer part of a straddle. Options on single stocks that are not "deep in the money" may constitute qualified covered calls, which generally are not subject to the straddle rules; the holding period on stock underlying qualified covered calls that are "in the money" although not "deep in the money" will be suspended during the period that such calls are outstanding. The straddle rules and the rules governing qualified covered calls may affect the character of gains (or losses) realized by an Underlying ETF by causing gains that would otherwise constitute long-term capital gains to be treated as short-term capital gains, and distributions that would otherwise constitute "qualified dividend income" or qualify for the dividends-received deduction to fail to satisfy the holding period requirements and therefore to be taxed as ordinary income or to fail to qualify for the dividends-received deduction, as the case may be. In addition, losses realized by an Underlying ETF on positions that are part of a straddle may be deferred under the straddle rules, rather than being taken into account in calculating the taxable income for the taxable year in which such losses are realized. Because only a few regulations implementing the straddle rules have been promulgated, the tax consequences to the Underlying ETFs of transactions in options, futures, forward contracts, and swap agreements are not entirely clear.

The Underlying ETFs may make one or more of the elections available under the Code which are applicable to straddles. If an Underlying ETF makes any of the elections, the amount, character and timing of gains or losses from the affected straddle positions will be determined under rules that vary according to the election(s) made. The rules applicable under certain of the elections operate to accelerate the recognition of gains or losses from the affected straddle positions. Because application of the straddle rules may affect the character of gains or losses, defer losses and/or accelerate the recognition of gains or losses from the affected straddle positions, the amount which must be distributed to shareholders (including the Fund), and which will be taxed to shareholders as ordinary income or long-term capital gain, may be increased or decreased substantially as compared to an Underlying ETF that did not engage in such hedging transactions.

In addition, the Underlying ETF's transactions in other derivative instruments (e.g., forward contracts and swap agreements), as well as any of its hedging, short sale, securities loan or similar transactions, may be subject to one or more special tax rules (e.g., notional principal contract, straddle, constructive sale, wash sale and short sale rules), which could affect the amount, timing and/or character of distributions to shareholders (including the Fund). The qualifying income and diversification requirements applicable to an Underlying ETF's assets may limit the extent to which the Underlying ETF will be able to engage in transactions in options, futures contracts, forward contracts, swap agreements, and other derivative instruments.

Rules governing the tax aspects of swap agreements and other derivative instruments are in a developing stage and are not entirely clear in certain respects. Accordingly, while the Underlying ETFs intend to account for such transactions in a manner it deems to be appropriate, the IRS might not accept such treatment. If it did not, the status of the Underlying ETFs as regulated investment companies - and consequently the status of the Fund as a regulated investment company - might be affected. Calamos Advisors intends to monitor developments in this area.

An adverse determination or future guidance by the IRS with respect to these rules (which determination or guidance could be retroactive) may affect whether the Underlying ETFs have has made sufficient distributions, and otherwise satisfied the relevant requirements, to maintain their qualification as regulated investment companies, which may affect whether the Fund has satisfied its relevant requirements to maintain its qualification as a regulated investment company and avoid the Fund-level tax.

Nature of Fund Investments

Certain of the Underlying ETF's investment practices are subject to special and complex federal income tax provisions that may, among other things, (i) disallow, suspend or otherwise limit the allowance of certain losses or deductions; (ii) convert lower taxed long-term capital gain into higher taxed short-term capital gain or ordinary income; (iii) convert an ordinary loss or a deduction into a capital loss (the deductibility of which is more limited); (iv) cause the Underlying ETF to recognize income or gain without a corresponding receipt of cash; (v) adversely affect the time as to when a purchase or sale of stock or securities is deemed to occur; and (vi) adversely alter the characterization of certain complex financial transactions. These provisions may therefor affect the amount, timing and character of distributions by the Underlying ETFs to the Fund and therefore to Fund shareholders.

Non-U.S. Taxes

Income and proceeds received by an Underlying ETF from sources within foreign countries may be subject to withholding and other taxes imposed by such countries, which would reduce the Underlying ETF's return on investments in such countries. Tax treaties between certain countries and the United States may reduce or eliminate such taxes. The Underlying Funds do not expect to be permitted to elect to pass to their shareholders non-income or other similar taxes paid or treated as paid by the Underlying ETFs, so shareholders of the Fund will not be entitled separately to claim a credit or deduction in respect of such payments. In addition, the Underlying ETF's investments in foreign securities or foreign currencies may increase or accelerate the Underlying ETF's recognition of ordinary income and may affect the timing or amount of the Underlying ETF's distributions, and therefore may affect the timing or amount of the Fund's distributions.

Investments in Certain Non-U.S. Corporations

If an Underlying ETF holds an equity interest in any "passive foreign investment companies" ("PFICs"), which are generally certain non-U.S. corporations that receive at least 75% of their annual gross income from passive sources (such as interest, dividends, certain rents and royalties or capital gains) or that hold at least 50% of their assets in investments producing such passive income, the Underlying ETF could be subject to U.S. federal income tax and additional interest charges on gains and certain distributions with respect to those equity interests, even if all the income or gain is timely distributed to the Fund. The Fund will not be able to pass through to its shareholders any credit or deduction for such taxes. The Underlying ETF may be able to make an election that could ameliorate these adverse tax consequences. For instance, the Underlying ETF may elect to mark the gains (and to a limited extent losses) in such holdings "to the market" as though it had sold (and, solely for purposes of this mark-to-market election, repurchased) its holdings in those PFICs on the last day of the Underlying ETF's taxable year. If the Underlying ETF was to make a mark-to-market election, the Underlying ETF would recognize as ordinary income any increase in the value of such PFIC shares, and as ordinary loss any decrease in such value to the extent it did not exceed prior increases included in income. Under this election, the Underlying ETF might be required to recognize in a year income in excess of its distributions from PFICs and its proceeds from dispositions of PFIC stock during that year, and such income would nevertheless be subject to the distribution requirement and would be taken into account for purposes of the 4% excise tax (described above). Dividends paid by PFICs are not treated as qualified dividend income.

Backup Withholding

The Fund may be required to withhold U.S. federal income tax from all taxable distributions and sale proceeds payable to shareholders who fail to provide the Fund with their correct taxpayer identification number or fail to make required certifications, or who have been notified by the Internal Revenue Service that they are subject to backup withholding. Corporate shareholders and certain other shareholders specified in the Code generally are exempt from such backup withholding. This withholding is not an additional tax. Any amounts withheld may be credited against the shareholder's U.S. federal income tax liability.

Non-U.S. Shareholders

U.S. taxation of a shareholder who, as to the United States, is a nonresident alien individual, a non-U.S. trust or estate, a non-U.S. corporation or non-U.S. partnership ("non-U.S. shareholder") depends on whether the income of the Fund is "effectively connected" with a U.S. trade or business carried on by the shareholder.

In addition to the rules described in this section concerning the potential imposition of withholding on distributions to non-U.S. persons, distributions to non-U.S. persons that are "financial institutions" may be subject to a withholding tax of 30% unless an agreement is in place between the financial institution and the Department of the Treasury to collect and disclose information about accounts, equity investments, or debt interests in the financial institution held by one or more U.S. persons or the institution is resident in a jurisdiction that has entered into such an agreement with the Department of the Treasury. For these purposes, a "financial institution" means any entity that (i) accepts deposits in the ordinary course of a banking or similar business; (ii) holds financial assets for the account of others as a substantial portion of its business; or (iii) is engaged (or holds itself out as being engaged) primarily in the business of investing, reinvesting or trading in securities, partnership interests, commodities or any interest (including a futures contract or option) in such securities, partnership interests or commodities. The Internal Revenue Service and the Department of the Treasury have issued proposed regulations providing that these withholding rules will not be applicable to the gross proceeds of share redemptions or capital gains dividends that the Fund pays.

Distributions to non-financial non-U.S. entities (other than publicly traded non-U.S. entities, entities owned by residents of U.S. possessions, non-U.S. governments, international organizations, or non-U.S. central banks), will also be subject to a withholding tax of 30% if the entity does not (i) certify that the entity does not have any substantial U.S. owners (ii) or provide the name, address and TIN of each substantial U.S. owner. The Internal Revenue Service and the Department of the Treasury have issued proposed regulations providing that these withholding rules will also not be applicable to the gross proceeds of share redemptions or capital gains dividends that the Fund pays.

Income Not Effectively Connected

If the income from the Fund is not "effectively connected" with a U.S. trade or business carried on by the non-U.S. shareholder, distributions of investment company taxable income will generally be subject to a U.S. tax of 30% (or lower treaty rate), which tax is generally withheld from such distributions.

Distributions of capital gain dividends and any amounts retained by the Fund which are properly reported by the Fund as undistributed capital gains will not be subject to U.S. tax at the rate of 30% (or lower treaty rate) unless the non-U.S. shareholder is a nonresident alien individual and is physically present in the United States for more than 182 days during the taxable year and meets certain other requirements. However, this 30% tax on capital gains of nonresident alien individuals who are physically present in the United States for more than the 182 day period only applies in exceptional cases because any individual present in the United States for more than 182 days during the taxable year is generally treated as a resident for U.S. income tax purposes; in that case, he or she would be subject to U.S. income tax on his or her worldwide income at the graduated rates applicable to U.S. citizens, rather than the 30% U.S. tax. In the case of a non-U.S. shareholder who is a nonresident alien individual, the Fund may be required to withhold U.S. income tax from distributions of net capital gain unless the non-U.S. shareholder certifies his or her non-U.S. status under penalties of perjury or otherwise establishes an exemption. If a non-U.S. shareholder is a nonresident alien individual, any gain such shareholder realizes upon the sale or exchange of such shareholder's Fund Shares in the United States will ordinarily be exempt from U.S. tax unless the gain is U.S. source income and such shareholder is physically present in the United States for more than 182 days during the taxable year and meets certain other requirements.

Distributions from the Fund that are properly reported by the Fund as an interest-related dividend attributable to certain interest income received by the Fund or as a short-term capital gain dividend attributable to certain net short-term capital gain income received by the Fund may not be subject to U.S. federal income taxes, including withholding taxes when received by certain non-U.S. investors, provided that the Fund makes certain elections and certain other conditions are met.

In addition, capital gain distributions attributable to gains from U.S. real property interests (including certain U.S. real property holding corporations) will generally be subject to U.S. withholding tax and may give rise to an obligation on the part of the non-U.S. shareholder to file a U.S. tax return.

Income Effectively Connected

If the income from the Fund is "effectively connected" with a U.S. trade or business carried on by a non-U.S. shareholder, then distributions of investment company taxable income and capital gain dividends, any amounts retained by the Fund which are properly reported by the Fund as undistributed capital gains and any gains realized upon the sale or exchange of Fund Shares will be subject to U.S. income tax at the graduated rates applicable to U.S. citizens, residents and domestic corporations. Non-U.S. corporate shareholders may also be subject to the branch profits tax imposed by the Code. The tax consequences to a non-U.S. shareholder entitled to claim the benefits of an applicable tax treaty may differ from those described herein. Non-U.S. shareholders are advised to consult their own tax advisors with respect to the particular tax consequences to them of an investment in the Fund.

Capital Loss Carryforward

Net capital gains of the Fund that are available for distribution to shareholders will be computed by taking into account any applicable capital loss carryforward.

Other Taxation

Fund shareholders may be subject to state, local and foreign taxes on their Fund distributions. Shareholders are advised to consult their own tax advisors with respect to the particular tax consequences to them of an investment in the Fund.

CUSTODIAN AND TRANSFER AGENT

State Street Bank and Trust Company ("State Street"), One Congress Street, Boston, Massachusetts 02114-2016, is the custodian for the assets of the Fund. The custodian is responsible for holding all cash and securities of the Fund, directly or through a book entry system, delivering and receiving payment for securities sold by the Fund, receiving and paying for securities purchased by the Fund, collecting income from investments of the Fund and performing other duties, all as directed by authorized persons of the Trust. The custodian does not exercise any supervisory functions in such matters as the purchase and sale of securities by the Fund, payment of dividends or payment of expenses of the Fund.

State Street also serves as transfer agent and dividend paying agent for the Fund.

FUND ACCOUNTING AND FINANCIAL ACCOUNTING AGENT

Under the arrangements with State Street to provide fund accounting services, State Street provides certain administrative and accounting services including providing daily reconciliation of cash, trades and positions; maintaining general ledger and capital stock accounts; preparing daily trial balance; calculating NAV; providing selected general ledger reports; preferred share compliance; calculating total returns; and providing monthly distribution analysis to the Fund. The Fund has also entered into an agreement with State Street pursuant to which State Street provides certain administration treasury services to the Fund. These services include: monitoring the calculation of expense accrual amounts for the Fund and making any necessary modifications; managing the Fund's expenses and expense payment processing; coordinating any expense reimbursement calculations and payment; calculating net investment income dividends and capital gain distributions; coordinating the audits for the Fund; preparing financial reporting statements for the Fund; preparing certain regulatory filings; and calculating asset coverage tests for certain Calamos Funds.

MISCELLANEOUS

Counsel. Ropes & Gray LLP, located at 191 North Wacker Drive, 32^nd Floor, Chicago, IL 60606, is counsel to the Trust.

Independent Registered Public Accounting Firm. [ ] an independent registered public accounting firm, is the Trust's independent auditor and is located at [ ]. [ ] audits and reports on the Fund's annual financial statements and performs audit, audit-related and other services when approved by the Trust's audit committee.

FINANCIAL STATEMENTS

Because the Fund has not yet commenced operations, financial statements are not yet available for the Fund. [ ] will audit the Fund's annual financial statements once the Fund becomes operational. A copy of the Fund's Annual Report, once available, may be obtained upon request and without charge by writing or by calling the Fund at 1-866-363-9219.

EXHIBIT A-DESCRIPTION OF RATINGS⁷

A rating of a rating service represents the service's opinion as to the credit quality of the security being rated. However, the ratings are general and are not absolute standards of quality or guarantees as to the creditworthiness of an issuer. Consequently, Calamos Advisors believes that the quality of debt securities in which the Fund invests should be continuously reviewed. A rating is not a recommendation to purchase, sell or hold a security, because it does not take into account market value or suitability for a particular investor. When a security has received a rating from more than one service, each rating should be evaluated independently. Ratings are based on current information furnished by the issuer or obtained by the ratings services from other sources that they consider reliable. Ratings may be changed, suspended or withdrawn as a result of changes in or unavailability of such information, or for other reasons.

The following is a description of the characteristics of ratings used by Moody's Investors Service ("Moody's") and Standard & Poor's Corporation, a division of The McGraw-Hill Companies ("S&P").

MOODY'S GLOBAL SHORT-TERM RATING SCALE

P-1: Issuers (or supporting institutions) rated Prime-1 have a superior ability to repay short-term debt obligations.

P-2: Issuers (or supporting institutions) rated Prime-2 have a strong ability to repay short-term debt obligations.

P-3: Issuers (or supporting institutions) rated Prime-3 have an acceptable ability to repay short-term obligations.

NP: Issuers (or supporting institutions) rated Not Prime do not fall within any of the Prime rating categories.

MOODY'S GLOBAL LONG-TERM RATING SCALE

Aaa-Obligations rated Aaa are judged to be of the highest quality, subject to the lowest level of credit risk.

Aa-Obligations rated Aa are judged to be of high quality and are subject to very low credit risk.

A-Obligations rated A are judged to be upper-medium grade and are subject to low credit risk.

Baa-Obligations rated Baa are judged to be medium-grade and subject to moderate credit risk and as such may possess certain speculative characteristics.

Ba-Obligations rated Ba are judged to be speculative and are subject to substantial credit risk.

B-Obligations rated B are considered speculative and are subject to high credit risk.

Caa-Obligations rated Caa are judged to be speculative of poor standing and are subject to very high credit risk.

Ca-Obligations rated Ca are highly speculative and are likely in, or very near, default, with some prospect of recovery of principal and interest.

C-Obligations rated C are the lowest rated and are typically in default, with little prospect for recovery of principal or interest.

Note: Moody's appends numerical modifiers 1, 2, and 3 to each generic rating classification from Aa through Caa. The modifier 1 indicates that the obligation ranks in the higher end of its generic rating category; the modifier 2 indicates a mid-range ranking; and the modifier 3 indicates a ranking in the lower end of that generic rating category. Additionally, a "(hyb)" indicator is appended to all ratings of hybrid securities issued by banks, insurers, finance companies, and securities firms.*

S&P SHORT-TERM ISSUE CREDIT RATINGS

A-1: A short-term obligation rated 'A-1' is rated in the highest category by S&P Global Ratings. The obligor's capacity to meet its financial commitments on the obligation is strong. Within this category, certain obligations are designated with a plus sign (+). This indicates that the obligor's capacity to meet its financial commitments on these obligations is extremely strong.

⁷ The ratings indicated herein are believed to be the most recent ratings available at the date of this prospectus for the securities listed. Ratings are generally given to securities at the time of issuance. While the rating agencies may from time to time revise such ratings, they undertake no obligation to do so, and the rating indicated do not necessarily represent ratings which will be given to these securities on the date of the Fund's fiscal year-end.

* By their terms, hybrid securities allow for the omission of scheduled dividends, interest, or principal payments, which can potentially result in impairment if such an omission occurs. Hybrid securities may also be subject to contractually allowable write-downs of principal that could result in impairment. Together with the hybrid indicator, the long-term obligation rating assigned to a hybrid security is an expression of the relative credit risk associated with that security.

A-2: A short-term obligation rated 'A-2' is somewhat more susceptible to the adverse effects of changes in circumstances and economic conditions than obligations in higher rating categories. However, the obligor's capacity to meet its financial commitments on the obligation is satisfactory.

A-3: A short-term obligation rated 'A-3' exhibits adequate protection parameters. However, adverse economic conditions or changing circumstances are more likely to weaken an obligor's capacity to meet its financial commitments on the obligation.

B: A short-term obligation rated 'B' is regarded as vulnerable and has significant speculative characteristics. The obligor currently has the capacity to meet its financial commitments; however, it faces major ongoing uncertainties that could lead to the obligor's inadequate capacity to meet its financial commitments.

C: A short-term obligation rated 'C' is currently vulnerable to nonpayment and is dependent upon favorable business, financial, and economic conditions for the obligor to meet its financial commitments on the obligation.

D: A short-term obligation rated 'D' is in default or in breach of an imputed promise. For non-hybrid capital instruments, the 'D' rating category is used when payments on an obligation are not made on the date due, unless S&P Global Ratings believes that such payments will be made within any stated grace period. However, any stated grace period longer than five business days will be treated as five business days. The 'D' rating also will be used upon the filing of a bankruptcy petition or the taking of a similar action and where default on an obligation is a virtual certainty, for example due to automatic stay provisions. A rating on an obligation is lowered to 'D' if it is subject to a distressed exchange offer.

S&P LONG-TERM ISSUE CREDIT RATINGS*

Issue credit ratings are based, in varying degrees, on S&P Global Ratings' analysis of the following considerations:

● The likelihood of payment - the capacity and willingness of the obligor to meet its financial commitments on an obligation in accordance with the terms of the obligation;

● The nature and provisions of the financial obligation, and the promise we impute; and

● The protection afforded by, and relative position of, the financial obligation in the event of a bankruptcy, reorganization, or other arrangement under the laws of bankruptcy and other laws affecting creditors' rights.

An issue rating is an assessment of default risk but may incorporate an assessment of relative seniority or ultimate recovery in the event of default. Junior obligations are typically rated lower than senior obligations, to reflect lower priority in bankruptcy, as noted above. (Such differentiation may apply when an entity has both senior and subordinated obligations, secured and unsecured obligations, or operating company and holding company obligations.)

AAA-An obligation rated 'AAA' has the highest rating assigned by S&P. The obligor's capacity to meet its financial commitments on the obligation is extremely strong.

AA-An obligation rated 'AA' differs from the highest-rated obligations only to a small degree. The obligor's capacity to meet its financial commitments on the obligation is very strong.

A-An obligation rated 'A' is somewhat more susceptible to the adverse effects of changes in circumstances and economic conditions than obligations in higher-rated categories. However, the obligor's capacity to meet its financial commitments on the obligation is still strong.

BBB-An obligation rated 'BBB' exhibits adequate protection parameters. However, adverse economic conditions or changing circumstances are more likely to weaken an obligor's capacity to meet its financial commitments on the obligation.

BB, B, CCC, CC and C-Obligations rated 'BB', 'B', 'CCC', 'CC', and 'C' are regarded as having significant speculative characteristics. 'BB' indicates the least degree of speculation and 'C' the highest. While such obligations will likely have some quality and protective characteristics, these may be outweighed by large uncertainties or major exposure to adverse conditions.

BB-An obligation rated 'BB' is less vulnerable to nonpayment than other speculative issues. However, it faces major ongoing uncertainties or exposure to adverse business, financial, or economic conditions that could lead to the obligor's inadequate capacity to meet its financial commitments on the obligation.

* Ratings from 'AA' to 'CCC' may be modified by the addition of a plus (+) or minus (-) sign to show relative standing within the rating categories.

B-An obligation rated 'B' is more vulnerable to nonpayment than obligations rated 'BB', but the obligor currently has the capacity to meet its financial commitments on the obligation. Adverse business, financial, or economic conditions will likely impair the obligor's capacity or willingness to meet its financial commitments on the obligation.

CCC-An obligation rated 'CCC' is currently vulnerable to nonpayment, and is dependent upon favorable business, financial, and economic conditions for the obligor to meet its financial commitment on the obligation. In the event of adverse business, financial, or economic conditions, the obligor is not likely to have the capacity to meet its financial commitment on the obligation.

CC-An obligation rated 'CC' is currently highly vulnerable to nonpayment. The 'CC' rating is used when a default has not yet occurred, but S&P expects default to be a virtual certainty, regardless of the anticipated time to default.

C-An obligation rated 'C' is currently highly vulnerable to nonpayment, and the obligation is expected to have lower relative seniority or lower ultimate recovery compared with obligations that are rated higher.

D-An obligation rated 'D' is in payment default or in breach of an imputed promise. For non-hybrid capital instruments, the 'D' rating category is used when payments on an obligation are not made on the date due, unless S&P believes that such payments will be made within five business days in the absence of a stated grace period or within the earlier of the stated grace period or 30 calendar days. The 'D' rating also will be used upon the filing of a bankruptcy petition or the taking of similar action and where default on an obligation is a virtual certainty, for example due to automatic stay provisions. An obligation's rating is lowered to 'D' if it is subject to a distressed exchange offer.

NR-indicates that a rating has not been assigned or is no longer assigned.

Local Currency and Foreign Currency Ratings

S&P Global Ratings' issuer credit ratings make a distinction between foreign currency ratings and local currency ratings. A foreign currency rating on an issuer will differ from the local currency rating on it when the obligor has a different capacity to meet its obligations denominated in its local currency versus obligations denominated in a foreign currency.

CALAMOS ETF TRUST

PART C

OTHER INFORMATION

Item 28. EXHIBITS.

(a)	(i)	Amended and Restated Certificate of Trust of the Registrant (incorporated by reference to Exhibit (a)(ii) to Post-Effective Amendment No. 10 to Registrant's Registration Statement on Form N-1A, filed on January 23, 2023).
	(ii)	Second Amended and Restated Trust Instrument (incorporated by reference to Exhibit (a)(iii) to Post-Effective Amendment No. 10 to Registrant's Registration Statement on Form N-1A, filed on January 23, 2023).
(b)	Bylaws of the Registrant (incorporated by reference to Exhibit (b) to Post-Effective Amendment No. 10 to Registrant's Registration Statement on Form N-1A, filed on January 23, 2023).
(c)	See Articles IV, V, and VI of Exhibit (a)(ii) above and Article V of Exhibit (b) above.
(d)	(i)	Investment Advisory Agreement dated January 10, 2023 by and between Calamos ETF Trust and Calamos Antetokounmpo Asset Management LLC (incorporated by reference to Exhibit (d)(i) to Post-Effective Amendment No. 10 to Registrant's Registration Statement on Form N-1A, filed on January 23, 2023).
	(ii)	Sub-Advisory Agreement dated January 10, 2023 by and among Calamos Antetokounmpo Asset Management LLC, Calamos Advisors LLC and Calamos ETF Trust (incorporated by reference to Exhibit (d)(ii) to Post-Effective Amendment No. 10 to Registrant's Registration Statement on Form N-1A, filed on January 23, 2023).
	(iii)	Investment Advisory Agreement dated September 1, 2023 by and between Calamos ETF Trust and Calamos Advisors LLC (incorporated by reference to Exhibit (d)(iii) to Post-Effective Amendment No. 16 to Registrant's Registration Statement on Form N-1A, filed on September 28, 2023).
	(iv)	Amendment, dated September 26, 2023, regarding Calamos CEF Income & Arbitrage ETF, to Investment Advisory Agreement by and between Calamos ETF Trust and Calamos Advisors LLC (incorporated by reference to Exhibit (d)(iv) to Post-Effective Amendment No. 18 to Registrant's Registration Statement on Form N-1A, filed on November 21, 2023).
	(v)	Amendment, dated December 12, 2023, regarding Calamos Alternative Nasdaq & Bond ETF, to Investment Advisory Agreement by and between Calamos ETF Trust and Calamos Advisors LLC (incorporated by reference to Exhibit (d)(v) to Post-Effective Amendment No. 22 to Registrant's Registration Statement on Form N-1A, filed on January 10, 2024).
	(vi)	Amendment, dated April 18, 2024, regarding Calamos S&P 500 Structured Alt Protection ETF - May, Calamos S&P 500 Structured Alt Protection ETF - August, Calamos S&P 500 Structured Alt Protection ETF - November, Calamos S&P 500 Structured Alt Protection ETF - February, Calamos Nasdaq 100 Structured Alt Protection ETF - June, Calamos Nasdaq 100 Structured Alt Protection ETF - September, Calamos Nasdaq 100 Structured Alt Protection ETF - December, and Calamos Nasdaq 100 Structured Alt Protection ETF - March, to Investment Advisory Agreement by and between Calamos ETF Trust and Calamos Advisors LLC (incorporated by reference to Exhibit (d)(vi) to Post-Effective Amendment No. 30 to Registrant's Registration Statement on Form N-1A, filed on April 22, 2024).
	(vii)	Amendment, dated May 22, 2024 regarding Calamos Russell 2000 Structured Alt Protection ETF - July, Calamos Russell 2000 Structured Alt Protection ETF - October, Calamos Russell 2000 Structured Alt Protection ETF - January, and Calamos Russell 2000 Structured Alt Protection ETF - April to Investment Advisory Agreement by and between Calamos ETF Trust and Calamos Advisors LLC (incorporated by reference to Exhibit (d)(vii) to Post-Effective Amendment No. 33 to Registrant's Registration Statement on Form N-1A, filed on June 13, 2024).
	(viii)	Amendment, dated [ ] regarding Calamos S&P 500 Structured Alt Protection ETF - January, Calamos S&P 500 Structured Alt Protection ETF - February, Calamos S&P 500 Structured Alt Protection ETF - March, Calamos S&P 500 Structured Alt Protection ETF - April, Calamos S&P 500 Structured Alt Protection ETF - June, Calamos S&P 500 Structured Alt Protection ETF - October, Calamos S&P 500 Structured Alt Protection ETF - November, and Calamos S&P 500 Structured Alt Protection ETF - December to Investment Advisory Agreement by and between Calamos ETF Trust and Calamos Advisors LLC (to be filed by amendment).
	(ix)	Amendment, dated [ ] regarding Calamos [Bitcoin Structured Alt Protection ETFs] to Investment Advisory Agreement by and between Calamos ETF Trust and Calamos Advisors LLC (to be filed by amendment).
	(x)	Amendment, dated [ ], regarding Calamos Laddered S&P 500 Structured Alt Protection ETF to Investment Advisory Agreement by and between Calamos ETF Trust and Calamos Advisors (to be filed by amendment).
(e)	(i)	ETF Distribution Agreement dated December 19, 2023 between Calamos ETF Trust and Calamos Financial Services LLC (incorporated by reference to Exhibit (e)(iv) to Post-Effective Amendment No. 22 to Registrant's Registration Statement on Form N-1A, filed on January 10, 2024).

	(ii)	First Amendment to ETF Distribution Agreement dated April 18, 2024 (incorporated by reference to Exhibit (e)(ii) to Post-Effective Amendment No. 30 to Registrant's Registration Statement on Form N-1A, filed on April 22, 2024).
	(iii)	Second Amendment to ETF Distribution Agreement dated May 22, 2024 (incorporated by reference to Exhibit (e)(iii) to Post-Effective Amendment No. 33 to Registrant's Registration Statement on Form N-1A, filed on June 13, 2024).
	(iv)	Third Amendment to ETF Distribution Agreement dated [ ] (to be filed by amendment).
(f)	Not applicable.
(g)	(i)	Master Custodian Agreement with State Street Bank and Trust Company, dated September 11, 2009 (incorporated by reference to Exhibit (g)(i) to Post-Effective Amendment No. 10 to Registrant's Registration Statement on Form N-1A, filed on January 23, 2023).
	(ii)	Notification of Additional Fund, dated December 21, 2022, pursuant to Master Custodian Agreement (incorporated by reference to Exhibit (g)(ii) to Post-Effective Amendment No. 10 to Registrant's Registration Statement on Form N-1A, filed on January 23, 2023).
	(iii)	Notification of Additional Funds, dated September 26, 2023, pursuant to Master Custodian Agreement (incorporated by reference to Exhibit (g)(iii) to Post-Effective Amendment No. 17 to Registrant's Registration Statement on Form N-1A, filed on October 6, 2023).
	(iv)	Notification of Additional Fund, dated December 12, 2023, pursuant to Master Custodian Agreement (incorporated by reference to Exhibit (g)(iv) to Post-Effective Amendment No. 22 to Registrant's Registration Statement on Form N-1A, filed on January 10, 2024).
	(v)	Notification of Additional Funds, dated April 24, 2024, pursuant to Master Custodian Agreement (incorporated by reference to Exhibit (g)(v) to Post-Effective Amendment No. 33 to Registrant's Registration Statement on Form N-1A, filed on June 13, 2024).
	(vi)	Notification of Additional Funds, dated May 29, 2024, pursuant to Master Custodian Agreement (incorporated by reference to Exhibit (g)(vi) to Post-Effective Amendment No. 33 to Registrant's Registration Statement on Form N-1A, filed on June 13, 2024).
	(vii)	Notification of Additional Funds, dated [ ], pursuant to Master Custodian Agreement (to be filed by amendment).
(h)	Other Material Contracts.
	(i)	Transfer Agency and Service Agreement, with State Street Bank and Trust Company dated as of March 21, 2014 (incorporated by reference to Exhibit (h)(2) to Pre-Effective Amendment No. 1 to Registrant's Registration Statement on Form N-1A, filed on May 28, 2014).
	(ii)	Notification of Additional Fund, dated December 21, 2022, pursuant to Transfer Agency and Service Agreement (incorporated by reference to Exhibit (h)(ii) to Post-Effective Amendment No. 10 to Registrant's Registration Statement on Form N-1A, filed on January 23, 2023).
	(iii)	Notification of Additional Funds, dated September 26, 2023, pursuant to Transfer Agency and Service Agreement (incorporated by reference to Exhibit (h)(iii) to Post-Effective Amendment No. 17 to Registrant's Registration Statement on Form N-1A, filed on October 6, 2023).
	(iv)	Notification of Additional Fund, dated December 12, 2023, pursuant to Transfer Agency and Service Agreement (incorporated by reference to Exhibit (h)(iv) to Post-Effective Amendment No. 22 to Registrant's Registration Statement on Form N-1A, filed on January 10, 2024).
	(v)	Notification of Additional Funds, dated April 24, 2024, pursuant to Transfer Agency and Service Agreement (incorporated by reference to Exhibit (h)(v) to Post-Effective Amendment No. 33 to Registrant's Registration Statement on Form N-1A, filed on June 13, 2024).
	(vi)	Notification of Additional Funds, dated May 29, 2024, pursuant to Transfer Agency and Service Agreement (incorporated by reference to Exhibit (h)(vi) to Post-Effective Amendment No. 33 to Registrant's Registration Statement on Form N-1A, filed on June 13, 2024).
	(vii)	Notification of Additional Funds, dated [ ], pursuant to Transfer Agency and Service Agreement (to be filed by amendment).
	(viii)	Administration Agreement, effective November 1, 2018, with State Street Bank (incorporated by reference to Exhibit (h)(iii) to Post-Effective Amendment No. 10 to Registrant's Registration Statement on Form N-1A, filed on January 23, 2023).
	(ix)	Notification of Additional Fund, dated December 21, 2022, pursuant to Administration Agreement (incorporated by reference to Exhibit (h)(iv) to Post-Effective Amendment No. 10 to Registrant's Registration Statement on Form N-1A, filed on January 23, 2023).
	(x)	Notification of Additional Funds, dated October 3, 2023, pursuant to Administration Agreement (incorporated by reference to Exhibit (h)(vi) to Post-Effective Amendment No. 17 to Registrant's Registration Statement on Form N-1A, filed on October 6, 2023).
	(xi)	Amendment to Administration Agreement, dated January 4, 2024 (incorporated by reference to Exhibit (h)(viii) to Post-Effective Amendment No. 25 to Registrant's Registration Statement on Form N-1A, filed on February 8, 2024).
	(xii)	Notification of Additional Funds, dated April 24, 2024, pursuant to Administration Agreement (incorporated by reference to Exhibit (h)(xii) to Post-Effective Amendment No. 33 to Registrant's Registration Statement on Form N-1A, filed on June 13, 2024).

	(xiii)	Notification of Additional Funds, dated May 29, 2024, pursuant to Administration Agreement (incorporated by reference to Exhibit (h)(xiii) to Post-Effective Amendment No. 33 to Registrant's Registration Statement on Form N-1A, filed on June 13, 2024).
	(xiv)	Notification of Additional Funds, dated [ ], pursuant to Administration Agreement (to be filed by amendment).
	(xv)	Master Services Agreement, dated March 15, 2004, with State Street Bank and Trust Company (incorporated by reference to Exhibit (h)(v) to Post-Effective Amendment No. 10 to Registrant's Registration Statement on Form N-1A, filed on January 23, 2023).
	(xvi)	Notification of Additional Funds, dated December 21, 2022, pursuant to the Master Services Agreement (incorporated by reference to Exhibit (h)(vi) to Post-Effective Amendment No. 10 to Registrant's Registration Statement on Form N-1A, filed on January 23, 2023).
	(xvii)	Notification of Additional Funds, dated September 26, 2023, pursuant to the Master Services Agreement (incorporated by reference to Exhibit (h)(ix) to Post-Effective Amendment No. 17 to Registrant's Registration Statement on Form N-1A, filed on October 6, 2023).
	(xviii)	Notification of Additional Fund, dated December 12, 2023, pursuant to the Master Services Agreement (incorporated by reference to Exhibit (h)(xii) to Post-Effective Amendment No. 22 to Registrant's Registration Statement on Form N-1A, filed on January 10, 2024).
	(xix)	Notification of Additional Funds, dated April 24, 2024, pursuant to Master Services Agreement (incorporated by reference to Exhibit (h)(xix) to Post-Effective Amendment No. 33 to Registrant's Registration Statement on Form N-1A, filed on June 13, 2024).
	(xx)	Notification of Additional Funds, dated May 29, 2024, pursuant to Master Services Agreement (incorporated by reference to Exhibit (h)(xx) to Post-Effective Amendment No. 33 to Registrant's Registration Statement on Form N-1A, filed on June 13, 2024).
	(xxi)	Notification of Additional Funds, dated [ ], pursuant to Master Services Agreement (to be filed by amendment).
	(xxii)	Master Services Agreement, effective as of October 16, 2023, with Ernst & Young LLP (incorporated by reference to Exhibit (h)(xvi) to Post-Effective Amendment No. 29 to Registrant's Registration Statement on Form N-1A, filed on April 12, 2024).
	(xxiii)	Form of Authorized Participant Agreement (incorporated by reference to Exhibit (h)(vii) to Post-Effective Amendment No. 10 to Registrant's Registration Statement on Form N-1A, filed on January 23, 2023).
	(xxiv)	Revised Form of Authorized Participant Agreement (incorporated by reference to Exhibit (h)(xiii) to Post-Effective Amendment No. 22 to Registrant's Registration Statement on Form N-1A, filed on January 10, 2024).
(i)	Legal Opinion and Consent (to be filed by amendment).
(j)	Not applicable.
(k)	Not applicable.
(l)	Not applicable.
(m)	Rule 12b-1 Plan (incorporated by reference to Exhibit (m) to Post-Effective Amendment No. 10 to Registrant's Registration Statement on Form N-1A, filed on January 23, 2023).
	(i)	Amendment to Rule 12b-1 Plan dated September 26, 2023 (incorporated by reference to Exhibit (m)(i) to Post-Effective Amendment No. 16 to Registrant's Registration Statement on Form N-1A, filed on September 28, 2023).
	(ii)	Amendment to Rule 12b-1 Plan dated December 12, 2023 (incorporated by reference to Exhibit (m)(ii) to Post-Effective Amendment No. 22 to Registrant's Registration Statement on Form N-1A, filed on January 10, 2024).
	(iii)	Amendment to Rule 12b-1 Plan dated April 18, 2024 (incorporated by reference to Exhibit (m)(iii) to Post-Effective Amendment No. 30 to Registrant's Registration Statement on Form N-1A, filed on April 22, 2024).
	(iv)	Amendment to Rule 12b-1 Plan dated May 22, 2024 (incorporated by reference to Exhibit (m)(iv) to Post-Effective Amendment No. 33 to Registrant's Registration Statement on Form N-1A, filed on June 13, 2024).
	(v)	Amendment to Rule 12b-1 Plan dated [ ] (to be filed by amendment).
(n)	Not applicable.
(o)	Not applicable.
(p)	Code of Ethics.
	(i)	Code of Ethics of Calamos Antetokounmpo Asset Management LLC ("CGAM"), dated June 21, 2023 (incorporated by reference to Exhibit (p)(i) to Post-Effective Amendment No. 29 to Registrant's Registration Statement on Form N-1A, filed on April 12, 2024).
	(ii)	Code of Ethics and Insider Trading Policy of Registrant, Calamos Advisors LLC, Calamos Financial Services LLC and certain affiliated entities, dated March 28, 2024 (incorporated by reference to Exhibit (p)(ii) to Post-Effective Amendment No. 30 to Registrant's Registration Statement on Form N-1A, filed on April 22, 2024).

(q)	Powers of Attorney (incorporated by reference to Exhibit (q) to Post-Effective Amendment No. 29 to Registrant's Registration Statement on Form N-1A, filed on April 12, 2024).

Item 29. CONTROL PERSONS.

No person is directly or indirectly controlled by or under common control with Calamos Laddered S&P 500 Structured Alt Protection ETF.

Item 30. INDEMNIFICATION.

Article IX of the Second Amended and Restated Trust Instrument of the Registrant (the "Trust Instrument") (Exhibit (a)(ii) to this registration statement) provides that, subject to certain exceptions and limitations, every person who is, or has been, a trustee or an officer or employee of the Trust or is or was serving at the request of the Trust as a trustee, director, officer, employee or agent of another organization in which the Trust has any interest as a shareholder, creditor or otherwise ("Covered Person") shall be indemnified by the Trust and each series to the fullest extent permitted by law against liability and against all expenses reasonably incurred or paid by him or her in connection with any claim, action, suit or proceeding in which he or she becomes involved as a party or otherwise by virtue of his or her being or having been a Covered Person and against amounts paid or incurred by him or her in the settlement thereof. To the extent required under the Investment Company Act of 1940, as amended, but only to such extent, no indemnification shall be provided hereunder to a Covered Person: (i) who shall have been adjudicated by a court or body before which the proceeding was brought to be liable to the Trust or its shareholders by reason of willful misfeasance, bad faith, gross negligence or reckless disregard of the duties involved in the conduct of his or her office; or (ii) in the event of a settlement, unless there has been a determination that such Covered Person did not engage in willful misfeasance, bad faith, gross negligence or reckless disregard of the duties involved in the conduct of his or her office: (A) by the court or other body approving the settlement; (B) by at least a majority of those trustees who are neither interested persons of the Trust nor are parties to the matter based upon a review of readily available facts (as opposed to a full trial-type inquiry); or (C) by written opinion of independent legal counsel based upon a review of readily available facts (as opposed to a full trial-type inquiry).

The Trust Instrument also provides that if any shareholder or former shareholder of any series is held personally liable solely by reason of his or her being or having been a shareholder and not because of his or her acts or omissions or for some other reason, the shareholder or former shareholder (or his or her heirs, executors, administrators or other legal representatives or, in the case of any entity, its general successor) shall be entitled out of the assets belonging to the applicable series to be held harmless from and indemnified against all loss and expense arising from such liability. The Trust, on behalf of the affected series, shall, upon request by such shareholder or former shareholder, assume the defense of any claim made against him or her for any act or obligation of the series and satisfy any judgment thereon from the assets belonging to the series. Neither the Trust nor the applicable series shall be responsible for satisfying any obligation arising from such a claim that has been settled by the shareholder without the prior written notice to, and consent of, the Trust. Except as otherwise specifically provided in this Trust Instrument or in the Bylaws, the Trust shall have no obligation to indemnify or hold harmless any shareholder against any loss or expense arising under any circumstances whether in connection with a proceeding of any kind or otherwise.

The Registrant, its trustees and officers, its investment adviser, the other investment companies advised by the adviser and certain persons affiliated with them are insured, within the limits and subject to the limitations of the insurance, against certain expenses in connection with the defense of actions, suits or proceedings, and certain liabilities that might be imposed as a result of such actions, suits or proceedings. The insurance expressly excludes coverage for any trustee or officer whose personal dishonesty, fraudulent breach of trust, lack of good faith, or intention to deceive or defraud has been finally adjudicated or may be established or who willfully fails to act prudently.

Insofar as indemnification for liabilities arising under the Securities Act of 1933 (the "Securities Act") may be permitted to trustees, officers, and controlling persons of the Registrant pursuant to the foregoing provisions, or otherwise, the Registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the Registrant of expenses incurred or paid by a trustee, officer, or controlling person of the Registrant in the successful defense of any action, suit, or proceeding) is asserted by such trustee, officer, or controlling person in connection with the securities being registered, the Registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

Item 31. BUSINESS AND OTHER CONNECTIONS OF INVESTMENT ADVISER.

The information in the Statement of Additional Information under the captions "Management" and "Investment Advisory Services" is incorporated by reference.

Item 32. PRINCIPAL UNDERWRITER.

(a)	[ ] serves as principal underwriter for the following investment companies registered under the Investment Company Act of 1940, as amended: [to be completed by amendment]

(b)	The following are the Officers and Manager of the Distributor, the Registrant's underwriter. The Distributor's main business address is [ ]. [to be completed by amendment]

(c)	There are no commissions or other compensation received from the Registrant directly or indirectly, by any principal underwriter who is not an affiliated person of the Registrant or an affiliated person of an affiliated person.

Item 33. LOCATION OF ACCOUNTS AND RECORDS.

All such accounts, books, and other documents are maintained at the offices of the Registrant, at the offices of the Registrant's investment adviser, Calamos Advisors LLC, and [ ] , the Registrant's principal underwriter, [ ], or at the offices of the custodian and transfer agent, [ ]

[to be completed by amendment]

Item 34. MANAGEMENT SERVICES.

None.

Item 35. UNDERTAKINGS.

None.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, as amended, the Registrant certifies that it has duly caused this registration statement to be signed on its behalf by the undersigned, duly authorized, in the City of Naperville, and the State of Illinois on the 21st day of August 2024.

	Calamos ETF Trust
	By:	/s/ John P. Calamos, Sr.
		John P. Calamos, Sr.
		Trustee and President

Pursuant to the requirements of the Securities Act of 1933, this registration statement has been signed below by the following persons in the capacities and on the dates indicated.

Name		Title		Date
/s/ John P. Calamos, Sr.		Trustee and President (principal executive officer)		August 21, 2024
John P. Calamos, Sr.
/s/ John E. Neal*		Trustee		August 21, 2024
John E. Neal
/s/ William Rybak*		Trustee		August 21, 2024
William Rybak
/s/ Virginia G. Breen*		Trustee		August 21, 2024
Virginia G. Breen
/s/ Lloyd A. Wennlund*		Trustee		August 21, 2024
Lloyd A. Wennlund
/s/ Karen L. Stuckey*		Trustee		August 21, 2024
Karen L. Stuckey
/s/ Christopher M. Toub*		Trustee		August 21, 2024
Christopher M. Toub
/s/ Thomas E. Herman		Vice President and Chief Financial Officer (principal accounting officer)		August 21, 2024
Thomas E. Herman

*	An original power of attorney authorizing John P. Calamos, Sr. to execute this Registration Statement, and amendments thereto, for each of the trustees of the Registrant on whose behalf this Registration Statement is filed, was previously executed, and previously filed as an exhibit.

	By:	/s/ John P. Calamos, Sr.
		John P. Calamos, Sr.
		Attorney-in-Fact
		August 21, 2024