Summary Prospectus by Investment Company - Form 497K

Supplement dated July 26, 2024

to the Prospectus and Summary Prospectus, each as supplemented as applicable, of each of the following funds (each, a Fund, and collectively, the Funds):

Fund	Prospectus and Summary Prospectus Dated
Columbia Funds Series Trust
Columbia Short Duration Municipal Bond Fund	9/1/2023
Columbia Funds Series Trust II
Columbia Ultra Short Duration Municipal Bond Fund	1/1/2024

Effective on August 1, 2024 (the Effective Date), the following changes are hereby made to each Fund's Prospectus and Summary Prospectus.

On the Effective Date, the information under the caption "Principal Investment Strategies" in the Summary Prospectus and in the "Summary of the Fund" and "More Information About the Fund" sections of the Prospectus is hereby amended to add the following:

The Fund may enter into tender option bond (TOB) transactions and may invest in derivatives, such as floating rate municipal securities (floaters) and inverse floating rate municipal securities (inverse floaters) to add incremental income, futures (including interest rate and Treasury bond futures) to manage duration and hedge against changes in interest rates, and swaps, including Municipal Market Data Rate Locks (MMD Rate Locks) to manage duration and hedge against changes in interest rates. A TOB is a Trust in which the Fund deposits municipal securities owned by the Fund. The Trust then issues two types of securities, a floater which is typically purchased by a money market fund and an inverse floater which the Fund continues to hold. Inverse floaters provide the Fund with leveraged exposure to underlying municipal bonds whose interest payments vary inversely with changes in short-term tax-exempt interest rates.

The rest of the sections remain the same.

On the Effective Date, the information under the caption "Principal Risks" in the Summary Prospectus and in the "Summary of the Fund" and "More Information About the Fund" sections of the Prospectus is hereby amended to add the following:

Counterparty Risk. Counterparty risk is the risk that a counterparty to a transaction in a financial instrument held by the Fund or by a special purpose or structured vehicle invested in by the Fund may become insolvent or otherwise fail to perform its obligations. As a result, the Fund may obtain no or limited recovery of its investment, and any recovery may be significantly delayed.

Derivatives Risk. Derivatives may involve significant risks. Derivatives are financial instruments with a value in relation to, or derived from, the value of an underlying asset(s) or other reference, such as an index, rate or other economic indicator (each an underlying reference). Derivatives may include those that are privately placed or otherwise exempt from SEC registration, including certain Rule 144A eligible securities. Derivatives could result in Fund losses if the underlying reference does not perform as anticipated. Use of derivatives is a highly specialized activity that can involve investment techniques, risks, and tax planning different from those associated with more traditional investment instruments. The Fund's derivatives strategy may not be successful and use of certain derivatives could result in substantial, potentially unlimited, losses to the Fund regardless of the Fund's actual investment. A relatively small movement in the price, rate or other economic indicator associated with the underlying reference may result in substantial losses for the Fund. Derivatives may be more volatile than other types of investments. The value of derivatives may be influenced by a variety of factors, including national and international political and economic developments. Potential changes to the regulation of the derivatives markets may make derivatives more costly, may limit the market for derivatives, or may otherwise adversely affect the value or performance of derivatives. Derivatives can increase the Fund's risk exposure to underlying references and their attendant risks, such as credit risk, market risk and interest rate risk, while potentially exposing the Fund to counterparty risk, leverage risk and liquidity risk.

Derivatives Risk - Futures Contracts Risk. A futures contract is an exchange-traded derivative transaction between two parties in which a buyer (holding the "long" position) agrees to pay a fixed price (or rate) at a specified future date for delivery of an underlying reference from a seller (holding the "short" position). The seller hopes that the market price on the delivery date is less than the agreed upon price, while the buyer hopes for the contrary. Certain futures contract markets are highly volatile, and futures contracts may be illiquid. Futures exchanges may limit fluctuations in futures contract prices by imposing a maximum permissible daily price movement. The Fund may be disadvantaged if it is prohibited from executing a trade outside the daily permissible price movement. At or prior to maturity of a futures contract, the Fund may enter into an offsetting contract and may incur a loss to the extent there has been adverse movement in futures contract prices. The liquidity of the futures markets depends on participants entering into offsetting transactions rather than making or taking delivery. To the extent participants make or take delivery, liquidity in the futures market could be reduced. Because of the low margin deposits normally required in futures trading, it is possible that the Fund may employ a high degree of leverage in the portfolio. As a result, a relatively small price movement in a futures contract may result in substantial losses to the Fund, exceeding the amount of the margin paid. For certain types of futures contracts, losses are potentially unlimited. Futures markets

are highly volatile and the use of futures may increase the volatility of the Fund's NAV. Futures contracts can increase the Fund's risk exposure to underlying references and their attendant risks, such as credit risk, market risk and interest rate risk, while potentially exposing the Fund to counterparty risk, leverage risk and liquidity risk.

Derivatives Risk - Inverse Floaters Risk. Inverse variable or floating rate obligations, sometimes referred to as inverse floaters, are a type of over-the-counter derivative debt instrument with a variable or floating coupon rate that moves in the opposite direction of an underlying reference, typically short-term interest rates. While inverse floaters tend to provide more income than similar term and credit quality fixed-rate bonds, they also exhibit greater volatility in price movement, which could result in significant losses for the Fund. An inverse floater may have the effect of investment leverage to the extent that its coupon rate varies by a magnitude that exceeds the magnitude of the change in the index or reference rate of interest, which could result in increased losses for the Fund. Inverse floaters can increase the Fund's risk exposure to underlying references and their attendant risks, such as credit risk, market risk and interest rate risk, while potentially exposing the Fund to counterparty risk, leverage risk and liquidity risk.

Derivatives Risk - Swaps Risk. In a typical swap transaction, two parties agree to exchange the return earned on a specified underlying reference for a fixed return or the return from another underlying reference during a specified period of time. Swaps may be difficult to value and may be illiquid. Swaps could result in Fund losses if the underlying asset or reference does not perform as anticipated. Swaps create significant investment leverage such that a relatively small price movement in a swap may result in immediate and substantial losses to the Fund. The Fund may only close out a swap with its particular counterparty, and may only transfer a position with the consent of that counterparty. Certain swaps, such as short swap transactions and total return swaps, have the potential for unlimited losses, regardless of the size of the initial position. Swaps can increase the Fund's risk exposure to underlying references and their attendant risks, such as credit risk, market risk and interest rate risk, while potentially exposing the Fund to counterparty risk, leverage risk and liquidity risk.

Impairment of Collateral Risk. The value of collateral, if any, securing a loan can decline, and may be insufficient to meet the borrower's obligations or difficult or costly to liquidate. In addition, the Fund's access to collateral may be limited by bankruptcy or other insolvency laws. Further, certain floating rate and other loans may not be fully collateralized and may decline in value.

Leverage Risk. Leverage occurs when the Fund increases its assets available for investment using borrowings, derivatives, or similar instruments or techniques. Use of leverage can produce volatility and may exaggerate changes in the NAV of Fund shares and in the return on the Fund's portfolio, which may increase the risk that the Fund will lose more than it has invested. If the Fund uses leverage, through the purchase of particular instruments such as derivatives, the Fund may experience capital losses that exceed the net assets of the Fund. Leverage can create an interest expense that may lower the Fund's overall returns. Leverage presents the opportunity for increased net income and capital gains, but may also exaggerate the Fund's volatility and risk of loss. There can be no guarantee that a leveraging strategy will be successful.

Tender Option Bond Risk. Tender option bond (TOB) transactions expose the Fund to leverage and credit risk, and generally involve greater risk than direct investments in fixed rate municipal bonds, including the risk of loss of principal. The interest payments that the Fund would typically receive in connection with a TOB transaction (inverse floaters) vary inversely with short-term interest rates and will be reduced (and potentially eliminated) when short-term interest rates increase. In addition, the Fund will be subject to leverage risk to the extent that the Fund uses the proceeds that it receives from a TOB transaction to invest in other securities. The Fund's investment in a TOB will generally underperform the market for fixed rate municipal securities when interest rates rise. The value of and market for such inverse floaters can be volatile and can have limited liquidity. Investments in inverse floaters issued in TOB transactions are derivative instruments and, therefore, are also subject to the risks generally applicable to investments in derivatives.

The rest of the sections remain the same.

Catherine Stienstra has announced her decision to retire as Senior Portfolio Manager and Head of Municipal Bond Investments, effective mid-2025. At that time, Ms. Stienstra will cease to serve as a portfolio manager of the Funds.

On the Effective Date, the information under the subsection "Fund Management" in the Summary Prospectus and in the "Summary of the Fund" section of the Prospectus is hereby amended to add the following:

Portfolio Management	Title	Role with Fund	Managed Fund Since
Paul Fox, CFA	Senior Portfolio Manager	Portfolio Manager	August 2024

The rest of the section remains the same.

On the Effective Date, the portfolio manager information under the heading "Primary Service Provider Contracts - Portfolio Managers" in the "More Information About the Fund" section of the Prospectus is hereby amended to add the following:

Portfolio Management	Title	Role with Fund	Managed Fund Since
Paul Fox, CFA	Senior Portfolio Manager	Portfolio Manager	August 2024

Mr. Fox joined one of the Columbia Management legacy firms or acquired business lines in 1999. Mr. Fox began his investment career in 1990 and earned a B.S. in Finance from the University of Massachusetts and an M.B.A. from Suffolk University.

The rest of the section remains the same.

Shareholders should retain this Supplement for future reference.