Primary Offering Prospectus - Form 424B2

Autocallable Contingent Coupon Equity Linked Securities Linked to the Worst Performing of the Dow Jones Industrial Average^TM and the S&P 500 Dynamic Participation Index Due November 29, 2029

(Key Terms continued on next page)

(1) Citigroup Global Markets Holdings Inc. currently expects that the estimated value of the securities on the pricing date will be at least $919.00 per security, which will be less than the issue price. The estimated value of the securities is based on CGMI's proprietary pricing models and our internal funding rate. It is not an indication of actual profit to CGMI or other of our affiliates, nor is it an indication of the price, if any, at which CGMI or any other person may be willing to buy the securities from you at any time after issuance. See "Valuation of the Securities" in this pricing supplement.

(2) CGMI will receive an underwriting fee of up to $12.50 for each security sold in this offering. The total underwriting fee and proceeds to issuer in the table above give effect to the actual total underwriting fee. For more information on the distribution of the securities, see "Supplemental Plan of Distribution" in this pricing supplement. In addition to the underwriting fee, CGMI and its affiliates may profit from expected hedging activity related to this offering, even if the value of the securities declines. See "Use of Proceeds and Hedging" in the accompanying prospectus.

(3) The per security proceeds to issuer indicated above represent the minimum per security proceeds to issuer for any security, assuming the maximum per security underwriting fee. As noted above, the underwriting fee is variable.

Investing in the securities involves risks not associated with an investment in conventional debt securities. See "Summary Risk Factors" beginning on page PS-6.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of the securities or determined that this pricing supplement and the accompanying product supplement, underlying supplement, prospectus supplement and prospectus are truthful or complete. Any representation to the contrary is a criminal offense.

You should read this pricing supplement together with the accompanying product supplement, underlying supplement, prospectus supplement and prospectus, which can be accessed via the hyperlinks below:

Product Supplement No. EA-04-10 dated March 7, 2023Underlying Supplement No. 11 dated March 7, 2023
Prospectus Supplement and Prospectus each dated March 7, 2023

The securities are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency, nor are they obligations of, or guaranteed by, a bank.

Additional Information

The terms of the securities are set forth in the accompanying product supplement, prospectus supplement and prospectus, as supplemented by this pricing supplement. The accompanying product supplement, prospectus supplement and prospectus contain important disclosures that are not repeated in this pricing supplement. For example, the accompanying product supplement contains important information about how the closing value of each underlying will be determined and about adjustments that may be made to the terms of the securities upon the occurrence of market disruption events and other specified events with respect to each underlying. The accompanying underlying supplement contains important disclosures regarding the S&P 500^® Index, on which the S&P 500 Dynamic Participation Index is ultimately based, and information about the Dow Jones Industrial Average^TM that is not repeated in this pricing supplement. It is important that you read the accompanying product supplement, underlying supplement, prospectus supplement and prospectus together with this pricing supplement before deciding whether to invest in the securities. Certain terms used but not defined in this pricing supplement are defined in the accompanying product supplement.

Hypothetical Examples

The examples in the first section below illustrate how to determine whether a contingent coupon will be paid (and whether any previously unpaid contingent coupon payments will be paid) and whether the securities will be automatically called for redemption following a valuation date that is also a potential autocall date. The examples in the second section below illustrate how to determine the payment at maturity on the securities, assuming the securities are not automatically redeemed prior to maturity. The examples are solely for illustrative purposes, do not show all possible outcomes and are not a prediction of any payment that may be made on the securities.

The examples below are based on the following hypothetical values and do not reflect the actual initial underlying values, coupon barrier values or final buffer values of the underlyings. For the actual initial underlying value, coupon barrier value and final buffer value of each underlying, see the cover page of this pricing supplement. We have used these hypothetical values, rather than the actual values, to simplify the calculations and aid understanding of how the securities work. However, you should understand that the actual payments on the securities will be calculated based on the actual initial underlying value, coupon barrier value and final buffer value of each underlying, and not the hypothetical values indicated below. For ease of analysis, figures below have been rounded. The examples below assume that the contingent coupon rate is set at the lowest value indicated on the cover page of this pricing supplement. The actual contingent coupon rate will be determined on the pricing date.

Hypothetical Examples of Contingent Coupon Payments and any Payment upon Automatic Early Redemption Following a Valuation Date that is also a Potential Autocall Date

The three hypothetical examples below illustrate how to determine whether a contingent coupon will be paid and whether the securities will be automatically redeemed following a hypothetical valuation date that is also a potential autocall date, assuming that the closing values of the underlyings on the hypothetical valuation date are as indicated below.

Example 1: On hypothetical valuation date #1, the S&P 500 Dynamic Participation Index has the lowest underlying return and, therefore, is the worst performing underlying on the hypothetical valuation date. In this scenario, the closing value of the worst performing underlying on the hypothetical valuation date is greater than its coupon barrier value but less than its initial underlying value. As a result, investors in the securities would receive the contingent coupon payment on the related contingent coupon payment date and the securities would not be automatically redeemed.

Example 2: On hypothetical valuation date #2, the Dow Jones Industrial Average^TM has the lowest underlying return and, therefore, is the worst performing underlying on the hypothetical valuation date. In this scenario, the closing value of the worst performing underlying on the hypothetical valuation date is less than its coupon barrier value. As a result, investors would not receive any payment on the related contingent coupon payment date and the securities would not be automatically redeemed.

Investors in the securities will not receive a contingent coupon on the contingent coupon payment date following a valuation date if the closing value of the worst performing underlying on that valuation date is less than its coupon barrier value. Whether a contingent coupon is paid following a valuation date depends solely on the closing value of the worst performing underlying on that valuation date.

Example 3: On hypothetical valuation date #3, the Dow Jones Industrial Average^TM has the lowest underlying return and, therefore, is the worst performing underlying on the hypothetical valuation date. In this scenario, the closing value of the worst performing underlying on the hypothetical valuation date is greater than both its coupon barrier value and its initial underlying value. As a result, the securities would be automatically redeemed on the related contingent coupon payment date for an amount in cash equal to $1,000.00 plus the related contingent coupon payment plus any previously unpaid contingent coupon payments. Because no contingent coupon payment was received in connection with hypothetical valuation date #2, investors in the securities would also receive the previously unpaid contingent coupon payment on the related contingent coupon payment date.

If the hypothetical valuation date were not also a potential autocall date, the securities would not be automatically redeemed on the related contingent coupon payment date.

Hypothetical Examples of the Payment at Maturity on the Securities

The next three hypothetical examples illustrate the calculation of the payment at maturity on the securities, assuming that the securities have not been earlier automatically redeemed and that the final underlying values of the underlyings are as indicated below.

Example 4: On the final valuation date, the Dow Jones Industrial Average^TM has the lowest underlying return and, therefore, is the worst performing underlying on the final valuation date. In this scenario, the final underlying value of the worst performing underlying on the final valuation date is greater than its final buffer value. Accordingly, at maturity, you would receive the stated principal amount of the securities plus the contingent coupon payment due at maturity (assuming no previously unpaid contingent coupon payments), but you would not participate in the appreciation of any of the underlyings.

Example 5: On the final valuation date, the S&P 500 Dynamic Participation Index has the lowest underlying return and, therefore, is the worst performing underlying on the final valuation date. In this scenario, the final underlying value of the worst performing underlying on the final valuation date is less than its final buffer value. Accordingly, at maturity, you would receive a payment per security calculated as follows:

Payment at maturity = $1,000.00 + [$1,000.00 × (the underlying return of the worst performing underlying on the final valuation date + the buffer percentage)]

= $1,000.00 + [$1,000.00 × (-50.00% + 15.00%)]

= $1,000.00 + ($1,000.00 × -35.00%)

= $1,000.00 + -$350.00

= $650.00

In this scenario, because the final underlying value of the worst performing underlying on the final valuation date is less than its final buffer value, you would lose a portion of your investment in the securities. Your payment at maturity would reflect a loss of 1% of the stated principal amount of your securities for every 1% by which the depreciation of the worst performing underlying on the final valuation date has exceeded the buffer percentage. In addition, because the final underlying value of the worst performing underlying on the final valuation date is below its coupon barrier value, you would not receive any contingent coupon payment at maturity.

Example 6: On the final valuation date, the Dow Jones Industrial Average^TM has the lowest underlying return and, therefore, is the worst performing underlying on the final valuation date. In this scenario, the final underlying value of the worst performing underlying on the final valuation date is less than its final buffer value. Accordingly, at maturity, you would receive a payment per security calculated as follows:

Payment at maturity = $1,000.00 + [$1,000.00 × (the underlying return of the worst performing underlying on the final valuation date + the buffer percentage)]

= $1,000.00 + [$1,000.00 × (-80.00% + 15.00%)]

= $1,000.00 + ($1,000.00 × -65.00%)

= $1,000.00 + -$650.00

= $350.00

In this scenario, because the final underlying value of the worst performing underlying on the final valuation date is less than its final buffer value, you would lose a significant portion of your investment in the securities. Your payment at maturity would reflect a loss of 1% of the stated principal amount of your securities for every 1% by which the depreciation of the worst performing underlying on the final valuation date has exceeded the buffer percentage. In addition, because the final underlying value of the worst performing underlying on the final valuation date is below its coupon barrier value, you would not receive any contingent coupon payment at maturity.

It is possible that the closing value of the worst performing underlying will be less than its coupon barrier value on each valuation date and less than its final buffer value on the final valuation date, such that you will not receive any contingent coupon payments over the term of the securities (including any previously unpaid contingent coupon payments) and will receive significantly less than the stated principal amount of your securities at maturity.

Summary Risk Factors

An investment in the securities is significantly riskier than an investment in conventional debt securities. The securities are subject to all of the risks associated with an investment in our conventional debt securities (guaranteed by Citigroup Inc.), including the risk that we and Citigroup Inc. may default on our obligations under the securities, and are also subject to risks associated with each underlying. Accordingly, the securities are suitable only for investors who are capable of understanding the complexities and risks of the securities. You should consult your own financial, tax and legal advisors as to the risks of an investment in the securities and the suitability of the securities in light of your particular circumstances.

The following is a summary of certain key risk factors for investors in the securities. You should read this summary together with the more detailed description of risks relating to an investment in the securities contained in the section "Risk Factors Relating to the Securities" beginning on page EA-7 in the accompanying product supplement. You should also carefully read the risk factors included in the accompanying prospectus supplement and in the documents incorporated by reference in the accompanying prospectus, including Citigroup Inc.'s most recent Annual Report on Form 10-K and any subsequent Quarterly Reports on Form 10-Q, which describe risks relating to the business of Citigroup Inc. more generally.

Because there is not an active market for traded instruments referencing our outstanding debt obligations, CGMI determines our secondary market rate based on the market price of traded instruments referencing the debt obligations of Citigroup Inc., our parent company and the guarantor of all payments due on the securities, but subject to adjustments that CGMI makes in its sole discretion. As a result, our secondary market rate is not a market-determined measure of our creditworthiness, but rather reflects the market's perception of our parent company's creditworthiness as adjusted for discretionary factors such as CGMI's preferences with respect to purchasing the securities prior to maturity.

Non-U.S. investors should note that persons having withholding responsibility in respect of the securities may withhold on any coupon payment paid to a non-U.S. investor, generally at a rate of 30%. To the extent that we have withholding responsibility in respect of the securities, we intend to so withhold.

You should read carefully the discussion under "United States Federal Tax Considerations" and "Risk Factors Relating to the Securities" in the accompanying product supplement and "United States Federal Tax Considerations" in this pricing supplement. You should also consult your tax adviser regarding the U.S. federal tax consequences of an investment in the securities, as well as tax consequences arising under the laws of any state, local or non-U.S. taxing jurisdiction.

Risks Relating to the S&P 500 Dynamic Participation Index

Set forth below is a discussion of risks relating to the S&P 500 Dynamic Participation Index. The following discussion of risks relating to the S&P 500 Dynamic Participation Index should be read together with Annex A to this pricing supplement, which defines and further describes a number of the terms and concepts referred to in this section.

It is impossible to predict whether the S&P 500 Dynamic Participation Index will rise or fall. The actual future performance of the S&P 500 Dynamic Participation Index may bear no relation to the historical or hypothetical back-tested values of the S&P 500 Dynamic Participation Index.

The S&P 500 Dynamic Participation Index is a relatively new index with a limited history of actual performance. As a result, the S&P 500 Dynamic Participation Index may be riskier than another index with a more established record of performance.

Additional Terms of the Securities

Market disruption events. For purposes of determining whether a market disruption event occurs with respect to the S&P 500 Dynamic Participation Index, each reference to the "Underlying Index" in the section "Description of the Securities-Certain Additional Terms for Securities Linked to an Underlying Index-Definitions of Market Disruption Event and Scheduled Trading Day and Related Definitions" in the accompanying product supplement shall be deemed replaced with a reference to the "Underlying Index or the S&P 500^® Index".

Material modification of the S&P 500 Dynamic Participation Index. If the sponsor of the S&P 500 Dynamic Participation Index announces that it will make, or that it will undertake a consultation with respect to, a material change in the formula for or the method of calculating the S&P 500 Dynamic Participation Index or any other material modification of the S&P 500 Dynamic Participation Index (other than a modification prescribed in that formula or method to maintain the index in the event of changes in constituent stock and capitalization and other routine events) (any such announcement, a "material modification event"), then the issuer may, at its option, direct the calculation agent to calculate the closing level of the S&P 500 Dynamic Participation Index on each date of determination after the effective date of such change in accordance with the formula for and method of calculating the S&P 500 Dynamic Participation Index last in effect prior to the change. Such level, as calculated by the calculation agent, will be the closing value of the S&P 500 Dynamic Participation Index for all purposes. The terms set forth in this paragraph supersede the terms set forth in the accompanying product supplement with respect to the S&P 500 Dynamic Participation Index to the extent they are inconsistent with such terms. For purposes of determining whether there has been a material modification to the S&P 500 Dynamic Participation Index, a material modification to the S&P 500^® Index shall be treated as though it were a material modification to the S&P 500 Dynamic Participation Index. Furthermore, any modification to the S&P 500 Dynamic Participation Index will be treated as a material modification unless made under the following circumstances: (i) to exercise routine judgment in the administration of the rules, provided that such routine judgment will not include deviations or alterations to the rules designed to improve the financial performance of the index; (ii) to correct errors in implementation of the rules or calculations made pursuant to the rules; or (iii) to make an adjustment to respond to an unanticipated event outside of the control of the sponsor of the S&P 500 Dynamic Participation Index, such as a stock split, merger, listing or delisting, nationalization, or insolvency of a component of the index, a disruption in the financial markets for specific assets or in a particular jurisdiction, regulatory compliance requirement, force majeure or any other unanticipated event of similar magnitude and significance.

If, on any day during the term of the securities, the calculation agent determines that a material modification event has occurred, we will have the right, but not the obligation, to redeem the securities, in whole and not in part, by providing written notice of our election to exercise that right to the trustee (the date of such notice, the "early redemption notice date") on a redemption date of our election that is no later than the 30th business day immediately following the early redemption notice date or earlier than the fifth business day following the early redemption notice date. A material modification event need not be continuing on the early redemption notice date or on the redemption date. The amount due and payable on the securities upon such redemption will be equal to the early redemption amount determined as of the early redemption notice date.

The "early redemption amount" will be the fair value of the securities determined by the calculation agent as of the early redemption notice date in good faith and in a manner based upon (but not necessarily identical to) CGMI's then contemporaneous practices for determining a secondary market bid price for the securities and similar instruments. In determining the early redemption amount, the calculation agent may take into account proprietary pricing models and may make adjustments to those models or inputs to those models in good faith and in a commercially reasonable manner. The calculation agent may also take into account other facts, whether or not unique to us or our affiliates, in determining the early redemption amount so long as it is in good faith and commercially reasonable. The early redemption amount may result in a significant loss on your securities. See "Summary Risk Factors-If a material modification event occurs during the term of the securities, we may redeem the securities early for an amount that may result in a significant loss on your investment" in this pricing supplement.

Information About the Dow Jones Industrial Average^TM

The Dow Jones Industrial Average^TM is a price-weighted index rather than a market capitalization-weighted index. The Dow Jones Industrial Average^TM consists of 30 common stocks chosen as representative of the broad market of U.S. industry. It is calculated and maintained by S&P Dow Jones Indices LLC.

Please refer to the section "Equity Index Descriptions- The Dow Jones Industrial Average^TM" in the accompanying underlying supplement for additional information.

We have derived all information regarding the Dow Jones Industrial Average^TM from publicly available information and have not independently verified any information regarding the Dow Jones Industrial Average^TM. This pricing supplement relates only to the securities and not to the Dow Jones Industrial Average^TM. We make no representation as to the performance of the Dow Jones Industrial Average^TM over the term of the securities.

The securities represent obligations of Citigroup Global Markets Holdings Inc. (guaranteed by Citigroup Inc.) only. The sponsor of the Dow Jones Industrial Average^TM is not involved in any way in this offering and has no obligation relating to the securities or to holders of the securities.

Historical Information

The closing value of the Dow Jones Industrial Average^TM on October 30, 2024 was 42,141.54.

The graph below shows the closing value of the Dow Jones Industrial Average^TM for each day such value was available from January 2, 2014 to October 30, 2024. We obtained the closing values from Bloomberg L.P., without independent verification. You should not take historical closing values as an indication of future performance.

Information About the S&P 500 Dynamic Participation Index

For information about S&P 500 Dynamic Participation Index, see Annex A to this pricing supplement.

Hypothetical Back-tested and Historical Performance Information

This section contains hypothetical back-tested performance information for the S&P 500 Dynamic Participation Index calculated by S&P Dow Jones Indices LLC. All S&P 500 Dynamic Participation Index performance information prior to July 31, 2019 is hypothetical and back-tested, as the S&P 500 Dynamic Participation Index did not exist prior to that date. Hypothetical back-tested performance information is subject to significant limitations. The publisher of the S&P 500 Dynamic Participation Index developed the rules of the index with the benefit of hindsight-that is, with the benefit of being able to evaluate how the rules would have caused the S&P 500 Dynamic Participation Index to perform had it existed during the hypothetical back-tested period. The fact that the S&P 500 Dynamic Participation Index appreciated at any time during the hypothetical back-tested period may not therefore be an accurate or reliable indication of any fundamental aspect of the index methodology. Furthermore, the hypothetical back-tested performance of the S&P 500 Dynamic Participation Index might look different if it covered a different historical period. The market conditions that existed during the hypothetical back-tested period may not be representative of market conditions that will exist in the future.

It is impossible to predict whether the S&P 500 Dynamic Participation Index will rise or fall. By providing the hypothetical back-tested and historical performance information below, we are not representing that the S&P 500 Dynamic Participation Index is likely to achieve gains or losses similar to those shown. In fact, there are frequently sharp differences between hypothetical performance results and the actual results subsequently achieved by any particular investment. One of the limitations of hypothetical performance information is that it did not involve financial risk and cannot account for all factors that would affect actual performance. The actual future performance of the S&P 500 Dynamic Participation Index may bear no relation to its hypothetical back-tested or historical performance.

The closing value of the S&P 500 Dynamic Participation Index on October 30, 2024 was 963.63.

The graph below shows the hypothetical back-tested closing values of the S&P 500 Dynamic Participation Index for the period from January 2, 2014 to July 30, 2019, and historical closing values of the S&P 500 Dynamic Participation Index for the period from July 31, 2019 to October 30, 2024. All data to the left of the vertical red line in the graph below are hypothetical and back-tested. We obtained the closing values from Bloomberg L.P., without independent verification. You should not take the hypothetical back-tested and historical values of the S&P 500 Dynamic Participation Index as an indication of future performance.

United States Federal Tax Considerations

You should read carefully the discussion under "United States Federal Tax Considerations" and "Risk Factors Relating to the Securities" in the accompanying product supplement and "Summary Risk Factors" in this pricing supplement.

Due to the lack of any controlling legal authority, there is substantial uncertainty regarding the U.S. federal tax consequences of an investment in the securities. In connection with any information reporting requirements we may have in respect of the securities under applicable law, we intend (in the absence of an administrative determination or judicial ruling to the contrary) to treat the securities for U.S. federal income tax purposes as prepaid forward contracts with associated coupon payments that will be treated as gross income to you at the time received or accrued in accordance with your regular method of tax accounting. We expect that our counsel will advise us that, based on current market conditions, this treatment of the securities is reasonable under current law, but that it is unable to conclude affirmatively that this treatment is more likely than not to be upheld, and that alternative treatments are possible. The information set forth under this section remains subject to confirmation by our counsel following the pricing of the securities. If that information cannot be confirmed by our counsel, you may be asked to accept revisions to that information in connection with your purchase. Under these circumstances, if you decline to accept revisions to that information, your purchase of the securities will be canceled.

Assuming this treatment of the securities is respected and subject to the discussion in "United States Federal Tax Considerations" in the accompanying product supplement, the following U.S. federal income tax consequences should result under current law:

We do not plan to request a ruling from the IRS regarding the treatment of the securities. An alternative characterization of the securities could materially and adversely affect the tax consequences of ownership and disposition of the securities, including the timing and character of income recognized. In addition, the U.S. Treasury Department and the IRS have requested comments on various issues regarding the U.S. federal income tax treatment of "prepaid forward contracts" and similar financial instruments and have indicated that such transactions may be the subject of future regulations or other guidance. Furthermore, members of Congress have proposed legislative changes to the tax treatment of derivative contracts. Any legislation, Treasury regulations or other guidance promulgated after consideration of these issues could materially and adversely affect the tax consequences of an investment in the securities, possibly with retroactive effect. You should consult your tax adviser regarding possible alternative tax treatments of the securities and potential changes in applicable law.

Withholding Tax on Non-U.S. Holders. Because significant aspects of the tax treatment of the securities are uncertain, persons having withholding responsibility in respect of the securities may withhold on any coupon payment paid to Non-U.S. Holders (as defined in the accompanying product supplement), generally at a rate of 30%. To the extent that we have (or an affiliate of ours has) withholding responsibility in respect of the securities, we intend to so withhold. In order to claim an exemption from, or a reduction in, the 30% withholding, you may need to comply with certification requirements to establish that you are not a U.S. person and are eligible for such an exemption or reduction under an applicable tax treaty. You should consult your tax adviser regarding the tax treatment of the securities, including the possibility of obtaining a refund of any amounts withheld and the certification requirement described above.

As discussed under "United States Federal Tax Considerations-Tax Consequences to Non-U.S. Holders" in the accompanying product supplement, Section 871(m) of the Code and Treasury regulations promulgated thereunder ("Section 871(m)") generally impose a 30% withholding tax on dividend equivalents paid or deemed paid to Non-U.S. Holders with respect to certain financial instruments linked to U.S. equities ("U.S. Underlying Equities") or indices that include U.S. Underlying Equities. Section 871(m) generally applies to instruments that substantially replicate the economic performance of one or more U.S. Underlying Equities, as determined based on tests set forth in the applicable Treasury regulations. However, the regulations, as modified by an IRS notice, exempt financial instruments issued prior to January 1, 2027 that do not have a "delta" of one. Based on the terms of the securities and market conditions as of the date of this preliminary pricing supplement, we expect that the securities will not be treated as transactions that have a "delta" of one within the meaning of the regulations with respect to any U.S. Underlying Equity and, therefore, should not be subject to withholding tax under Section 871(m). However, the final determination regarding the treatment of the securities under Section 871(m) will be made as of the pricing date for the securities, and it is possible that the securities will be subject to withholding tax under Section 871(m) based on the circumstances as of that date.

A determination that the securities are not subject to Section 871(m) is not binding on the IRS, and the IRS may disagree with this treatment. Moreover, Section 871(m) is complex and its application may depend on your particular circumstances, including your other transactions. You should consult your tax adviser regarding the potential application of Section 871(m) to the securities.

We will not be required to pay any additional amounts with respect to amounts withheld.

You should read the section entitled "United States Federal Tax Considerations" in the accompanying product supplement.

You should also consult your tax adviser regarding all aspects of the U.S. federal income and estate tax consequences of an investment in the securities and any tax consequences arising under the laws of any state, local or non-U.S. taxing jurisdiction.

Supplemental Plan of Distribution

CGMI, an affiliate of Citigroup Global Markets Holdings Inc. and the underwriter of the sale of the securities, is acting as principal and will receive an underwriting fee of up to $12.50 for each security sold in this offering. The actual underwriting fee will be equal to the selling concession

provided to selected dealers, as described in this paragraph. From this underwriting fee, CGMI will pay selected dealers not affiliated with CGMI a variable selling concession of up to $12.50 for each security they sell. For the avoidance of doubt, any fees or selling concessions described in this pricing supplement will not be rebated if the securities are automatically redeemed prior to maturity.

See "Plan of Distribution; Conflicts of Interest" in the accompanying product supplement and "Plan of Distribution" in each of the accompanying prospectus supplement and prospectus for additional information.

Valuation of the Securities

CGMI calculated the estimated value of the securities set forth on the cover page of this pricing supplement based on proprietary pricing models. CGMI's proprietary pricing models generated an estimated value for the securities by estimating the value of a hypothetical package of financial instruments that would replicate the payout on the securities, which consists of a fixed-income bond (the "bond component") and one or more derivative instruments underlying the economic terms of the securities (the "derivative component"). CGMI calculated the estimated value of the bond component using a discount rate based on our internal funding rate. CGMI calculated the estimated value of the derivative component based on a proprietary derivative-pricing model, which generated a theoretical price for the instruments that constitute the derivative component based on various inputs, including the factors described under "Summary Risk Factors-The value of the securities prior to maturity will fluctuate based on many unpredictable factors" in this pricing supplement, but not including our or Citigroup Inc.'s creditworthiness. These inputs may be market-observable or may be based on assumptions made by CGMI in its discretionary judgment.

The estimated value of the securities is a function of the terms of the securities and the inputs to CGMI's proprietary pricing models. As of the date of this preliminary pricing supplement, it is uncertain what the estimated value of the securities will be on the pricing date because certain terms of the securities have not yet been fixed and because it is uncertain what the values of the inputs to CGMI's proprietary pricing models will be on the pricing date.

For a period of approximately three months following issuance of the securities, the price, if any, at which CGMI would be willing to buy the securities from investors, and the value that will be indicated for the securities on any brokerage account statements prepared by CGMI or its affiliates (which value CGMI may also publish through one or more financial information vendors), will reflect a temporary upward adjustment from the price or value that would otherwise be determined. This temporary upward adjustment represents a portion of the hedging profit expected to be realized by CGMI or its affiliates over the term of the securities. The amount of this temporary upward adjustment will decline to zero on a straight-line basis over the three-month temporary adjustment period. However, CGMI is not obligated to buy the securities from investors at any time. See "Summary Risk Factors-The securities will not be listed on any securities exchange and you may not be able to sell them prior to maturity."

Contact

Clients may contact their local brokerage representative. Third-party distributors may contact Citi Structured Investment Sales at (212) 723-7005.

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Annex A
Description of the S&P 500 Dynamic Participation Index

Overview

The S&P 500 Dynamic Participation Index is calculated, maintained and published by S&P Dow Jones Indices LLC. All information contained in this pricing supplement regarding the S&P 500 Dynamic Participation Index, including, without limitation, its make-up, method of calculation and changes in its components, has been derived from information provided by S&P Dow Jones Indices LLC, without independent verification. This information reflects the policies of, and is subject to change by, S&P Dow Jones Indices LLC. S&P Dow Jones Indices LLC has no obligation to continue to publish, and may discontinue publication of, the S&P 500 Dynamic Participation Index. The securities represent obligations of Citigroup Global Markets Holdings Inc. (guaranteed by Citigroup Inc.) only. S&P Dow Jones Indices LLC is not involved in any way in this offering and has no obligation relating to the securities or to holders of the securities. The S&P 500 Dynamic Participation Index was first published on July 31, 2019, and therefore has limited performance history.

The S&P 500 Dynamic Participation Index tracks the hypothetical performance of a dynamic "leverage overlay" methodology on the S&P 500^® Index (the "parent index"), which means that the S&P 500 Dynamic Participation Index reflects exposure to the parent index that may be leveraged up to 200%, as adjusted on a daily basis. The degree of exposure of the S&P 500 Dynamic Participation Index to the performance of the parent index is reset at the close of each trading day based on a comparison of the closing value of the parent index on the current trading day to the trailing 10-day average closing value of the parent index. If the closing value of the parent index on the current trading day is less than its trailing 10-day average, the S&P 500 Dynamic Participation Index will reflect leveraged (i.e., greater than 100%, but no more than 200%) exposure to the parent index over the next trading day. By contrast, if the closing value of the parent index on the current trading day is greater than or equal to its trailing 10-day average, the S&P 500 Dynamic Participation Index will simply reflect 100% exposure to the parent index over the next trading day.

The S&P 500 Dynamic Participation Index's dynamic leverage overlay methodology may be thought of as reflecting a "buy the dip" strategy. When the parent index has been trending down (as indicated by the current closing value being less than the trailing 10-day average), the S&P 500 Dynamic Participation Index takes that as a signal to "buy" (i.e., temporarily increase exposure to) the parent index. The investment thesis on which this methodology is based is that downturns in performance in the parent index tend to be short-lived and that the parent index will recover relatively quickly from any such downturns. By applying leverage when the parent index's current closing value is less than its trailing 10-day average, the S&P 500 Dynamic Participation Index attempts to enhance returns by offering greater than 100% participation in the anticipated recovery from the downturn.

However, there can be no assurance that the S&P 500 Dynamic Participation Index's investment thesis will prove correct or that the S&P 500 Dynamic Participation Index will effectively implement its investment thesis. If the parent index experiences a sustained downturn so that the current closing value of the parent index remains below its trailing 10-day average for an extended period of time, the S&P 500 Dynamic Participation Index will have exposure to that downturn on a leveraged basis. The S&P 500 Dynamic Participation Index may therefore significantly underperform the parent index. Moreover, the S&P 500 Dynamic Participation Index will be more volatile than the parent index because fluctuations in the value of the S&P 500 Dynamic Participation Index will always equal or exceed fluctuations in the value of the parent index. For these reasons, the S&P 500 Dynamic Participation Index is significantly riskier than the parent index. See "Summary Risk Factors-Risks Relating to the S&P 500 Dynamic Participation Index" in this pricing supplement.

The S&P 500 Dynamic Participation Index is described as tracking the "hypothetical" performance of the dynamic leverage overlay methodology described in this Annex because there is no actual portfolio of stocks to which any investor is entitled or in which any investor has any ownership or other interest. The S&P 500 Dynamic Participation Index is merely a mathematical calculation that is performed by reference to hypothetical exposure to the parent index.

The parent index consists of the common stocks of 500 issuers selected to provide a performance benchmark for the large capitalization segment of the U.S. equity markets. For more information about the parent index, see "Equity Index Descriptions-The S&P U.S. Indices" in the accompanying underlying supplement.

The S&P 500 Dynamic Participation Index is reported by Bloomberg L.P. under the ticker symbol "SPXDPU1."

Calculating the Exposure of the S&P 500 Dynamic Participation Index to the Parent Index

At the close of each trading day, the S&P 500 Dynamic Participation Index determines how much exposure it will have to the performance of the parent index over the next trading day by comparing the closing value of the parent index on the current trading day to the simple average of the closing values of the parent index on the 10 trading days up to and including the trading day immediately preceding the current trading day, which we refer to as the "trailing 10-day average". On any trading day, if the closing value of the parent index on the current trading day is less than the trailing 10-day average, then the S&P 500 Dynamic Participation Index will have leveraged (i.e., greater than 100%) exposure to the performance of the parent index over the next trading day. The amount of that leveraged exposure will be determined by:

For example, if the current closing value of the parent index is 1% less than the trailing 10-day average (as a percentage of the current closing value), then the leverage factor would be 50% (50 times 1%) and the overall leveraged exposure would be 150% (50% plus 100%). If the current closing value of the parent index is less than the trailing 10-day average by 2% or more (as a percentage of the current closing value), then the leverage factor would be the maximum leverage factor of 100% and the overall leveraged exposure would be equal to the maximum of 200%

(100% plus 100%). Leveraged exposure of 200% would mean that the performance of the S&P 500 Dynamic Participation Index would be 200% of the performance of the parent index. As an example, if the parent index declined by 1% at a time when the S&P 500 Dynamic Participation Index has 200% leveraged exposure to the parent index, then the S&P 500 Dynamic Participation Index would decline by 2% (leaving aside the effects of the excess return deduction described below).

If the closing value of the parent index on any trading day is greater than or equal to the trailing 10-day average, the S&P 500 Dynamic Participation Index will have 100% (i.e., 1-to-1, or unleveraged) exposure to the performance of the parent index over the next trading day. As an example, if the parent index increased by 1% at a time when the S&P 500 Dynamic Participation Index has 100% exposure to the parent index, then the S&P 500 Dynamic Participation Index would also increase by 1%.

The S&P 500 Dynamic Participation Index resets its exposure to the parent index on each trading day, so that the leveraged exposure that is determined at the end of each trading day applies only over the next trading day.

At any time when the S&P 500 Dynamic Participation Index has greater than 100% exposure to the parent index, the leveraged portion of the S&P 500 Dynamic Participation Index's return will be reduced by an "excess return deduction" based on the effective federal funds rate (prorated for the number of calendar days since the most recent trading day). This excess return deduction reduces the performance of the S&P 500 Dynamic Participation Index, and any increase in the effective federal funds rate will increase its negative effect.

In this Annex, "trading day" means a day when the U.S. equity markets are open.

Comparison of Hypothetical Back-Tested and Historical S&P 500 Dynamic Participation Index Performance Against Historical S&P 500^® Index Performance

The following graph sets forth a comparison of the hypothetical back-tested and historical performance of the S&P 500 Dynamic Participation Index against the historical performance of the parent index from January 3, 2017 through October 30, 2024, each normalized to have a closing value of 100.00 on January 3, 2017 to facilitate a comparison.

As described above, the leverage feature causes the S&P 500 Dynamic Participation Index to be more volatile than the parent index and can cause the S&P 500 Dynamic Participation Index to underperform the parent index when the parent index declines. This underperformance will be especially dramatic when the parent index experiences a rapid and significant decline for a sustained period of time.

For example, as shown in the graph below, from December 3, 2018 to December 24, 2018 (an approximately three-week period) the maximum peak-to-trough decline in the closing value of the S&P 500 Dynamic Participation Index, expressed as a percentage (the "maximum drawdown"), was -25.08%. For the same period for the parent index, the maximum drawdown was only -15.74%. In addition, from February 19, 2020 to March 23, 2020 (an approximately one month period) the maximum drawdown in the closing value of the S&P 500 Dynamic Participation Index was -56.96%. For the same period for the parent index, the maximum drawdown was only -33.92%. The underperformance of the S&P 500 Dynamic Participation Index relative to the parent index over these periods demonstrates how the S&P 500 Dynamic Participation Index will perform significantly worse than the parent index in a declining equity market where the decline continues for longer than a short period of time.

All S&P 500 Dynamic Participation Index performance information prior to July 31, 2019 is hypothetical and back-tested, as the S&P 500 Dynamic Participation Index did not exist prior to that date. Hypothetical back-tested performance information is subject to the significant limitations described above under "Information About the S&P 500 Dynamic Participation Index".

In the graph below, references to "SPXDPU1" are to the S&P 500 Dynamic Participation Index and references to "SPX" are to the S&P 500^® Index.

The following graph sets forth a comparison of the hypothetical back-tested and historical performance of the S&P 500 Dynamic Participation Index against the historical performance of the parent index from January 2, 2014 through October 30, 2024, each normalized to have a closing value of 100.00 on January 2, 2014 to facilitate a comparison.

All S&P 500 Dynamic Participation Index performance information prior to July 31, 2019 is hypothetical and back-tested, as the S&P 500 Dynamic Participation Index did not exist prior to that date. Hypothetical back-tested performance information is subject to the significant limitations described above under "Information About the S&P 500 Dynamic Participation Index".

In the graph below, references to "SPXDPU1" are to the S&P 500 Dynamic Participation Index and references to "SPX" are to the S&P 500^® Index.

PAST PERFORMANCE OF THE S&P 500 DYNAMIC PARTICIPATION INDEX AND RELATIVE PERFORMANCE BETWEEN THE S&P 500 DYNAMIC PARTICIPATION INDEX AND THE PARENT INDEX ARE NOT INDICATIVE OF FUTURE PERFORMANCE

License

S&P Dow Jones and Citigroup Global Markets Inc. have entered into an exclusive license agreement providing for the license to Citigroup Inc. and its other affiliates, in exchange for a fee, of the right to use the S&P 500 Dynamic Participation Index in connection with certain financial products, including the securities.

"Standard & Poor's", "S&P" and "S&P 500" are trademarks of Standard & Poor's Financial Services LLC. "Dow Jones" is a registered trademark of Dow Jones Trademark Holdings, LLC ("Dow Jones"). Trademarks have been licensed to S&P Dow Jones and have been licensed for use by Citigroup Inc. and its affiliates.

The license agreement between S&P Dow Jones and Citigroup Global Markets Inc. provides that the following language must be stated in this pricing supplement.

"The securities are not sponsored, endorsed, sold or promoted by S&P Dow Jones, Dow Jones, S&P or their respective affiliates (collectively, "S&P Dow Jones Indices"). S&P Dow Jones Indices make no representation or warranty, express or implied, to the holders of the securities or any member of the public regarding the advisability of investing in securities generally or in the securities particularly. S&P Dow Jones Indices' only relationship to Citigroup Inc. and its affiliates (other than transactions entered into in the ordinary course of business) is the licensing of certain trademarks, trade names and service marks of S&P Dow Jones Indices and of the S&P indices, which are determined, composed and calculated by S&P Dow Jones Indices without regard to Citigroup Inc., its affiliates or the securities. S&P Dow Jones Indices have no obligation to take the needs of Citigroup Inc., its affiliates or the holders of the securities into consideration in determining, composing or calculating the S&P indices. S&P Dow Jones Indices are not responsible for and have not participated in the determination of the timing of, prices at or quantities of the securities to be issued or in the determination or calculation of the equation by which the securities are to be converted into cash. S&P Dow Jones Indices have no obligation or liability in connection with the administration, marketing or trading of the securities."