SEC Form FWP filed by Citigroup Inc.

n The Index

n The Securities

Hypothetical Index Return on Valuation Date

Hypothetical Security Return

Hypothetical Payment at Maturity

50.00%

82.50%

$1,825.00

B

25.00%

41.25%

$1,412.50

5.00%

8.25%

$1,082.50

0.00%

0.00%

$1,000.00

-25.00%

0.00%

$1,000.00

A

-50.00%

0.00%

$1,000.00

-100.00%

0.00%

$1,000.00

Issuer:

Citigroup Global Markets Holdings Inc.

Guarantor:

Citigroup Inc.

Index:

The Citi Dynamic Asset Selector 5 Excess Return Index (ticker: “CIISDA5N”)

Pricing date:

October 28, 2025

Valuation date:

October 28, 2027

Maturity date:

November 2, 2027

Upside participation rate:

At least 165.00%*

CUSIP / ISIN:

17333MT45 / US17333MT456

Initial index level:

The closing level of the Index on the pricing date

Final index level:

The closing level of the Index on the valuation date

Index return:

(Final index level - initial index level) / initial index level

Return amount:

If the final index level is greater than the initial index level:

$1,000 × the index return × the upside participation rate

If the final index level is less than or equal to the initial index level:

$0

All payments on the securities are subject to the credit risk of Citigroup Global Markets Holdings Inc. and Citigroup Inc.

Payment at maturity:

You will receive at maturity for each security you then hold, the stated principal amount plus the return amount, which will be either zero or positive

Stated principal amount:

$1,000 per security

Preliminary pricing supplement:

Preliminary Pricing Supplement dated September 26, 2025

Selected Risk Considerations

•You may not receive any return on your investment in the securities. You will receive a positive return on your investment in the securities only if the Index appreciates from the initial index level to the final index level. If the final index level is less than or equal to the initial index level, you will receive only the stated principal amount for each security you hold at maturity.

•The securities do not pay interest.

•Your payment at maturity depends on the closing level of the Index on a single day.

•The securities are subject to the credit risk of Citigroup Global Markets Holdings Inc. and Citigroup Inc. If Citigroup Global Markets Holdings Inc. defaults on its obligations under the securities and Citigroup Inc. defaults on its guarantee obligations, you may not receive anything owed to you under the securities.

•Sale of the securities prior to maturity may result in a loss of principal.

•The securities will not be listed on any securities exchange and you may not be able to sell them prior to maturity.

•The estimated value of the securities on the pricing date will be less than the issue price. For more information about the estimated value of the securities, see the accompanying preliminary pricing supplement.

•The value of the securities prior to maturity will fluctuate based on many unpredictable factors.

•The issuer and its affiliates may have conflicts of interest with you.

•The Index is a trend-following index and is subject to the limitations inherent in all trend-following methodologies, including the fact that past performance is no guarantee of future performance. Furthermore, the Index’s trend-following methodology may be unsuccessful even if past trends do prove to be indicative of future performance, because the Trend Signal may not accurately capture the trend or the Index may not change its Selected Portfolio quickly enough in response to changes in the Market Regime.

•Each Constituent is a futures-based index and is therefore expected to reflect the implicit cost of a financed position in its Reference Asset. This implicit financing cost will adversely affect the level of each Constituent and cause each Constituent to underperform its Reference Asset. Any increase in market interest rates will be expected to increase this implicit financing cost and will further adversely affect the performance of the Constituents and, therefore, the performance of the Index.

•The Index rules limit the exposure the Index may have to the U.S. Equity Futures Constituent and, as a result, the Index is likely to significantly underperform equities in rising equity markets.

•The Index will have significant exposure to the U.S. Treasury Futures Constituent, which has limited return potential and significant downside potential, particularly in times of rising interest rates.

•The volatility-targeting feature significantly reduces the potential for Index gains. At any time when the Index has less than 100% exposure to the Selected Portfolio, the Index will participate in only a limited degree of the performance of the Selected Portfolio.

•The Index’s allocation methodology may not be successful if the U.S. Equity Futures Constituent and the U.S. Treasury Futures Constituent decline at the same time.

•The Index may fail to maintain its volatility target. Because there is a time lag inherent in the Index’s volatility targeting feature, the Index may retain significant exposure to the U.S. Equity Futures Constituent long after a period of heightened volatility has begun, which may result in significant Index declines.

•The performance of the Index will be reduced by an index fee.

•The Index was launched on June 13, 2016 and, therefore, has a limited performance history.

•The Index follows fixed rules and will not be actively managed.

The above summary of selected risks does not describe all of the risks associated with an investment in the securities. You should read the accompanying preliminary pricing supplement and index supplement for a more complete description of risks relating to the securities.

Additional Information

Citigroup Global Markets Holdings Inc. and Citigroup Inc. have filed registration statements (including the accompanying preliminary pricing supplement, index supplement, prospectus supplement and prospectus) with the Securities and Exchange Commission (“SEC”) for the offering to which this communication relates. Before you invest, you should read the accompanying preliminary pricing supplement, index supplement, prospectus supplement and prospectus in those registration statements (File Nos. 333-270327 and 333-270327-01) and the other documents Citigroup Global Markets Holdings Inc. and Citigroup Inc. have filed with the SEC for more complete information about Citigroup Global Markets Holdings Inc., Citigroup Inc. and this offering. You may obtain these documents without cost by visiting EDGAR on the SEC website at www.sec.gov. Alternatively, you can request these documents by calling toll-free 1-800-831-9146.

Filed pursuant to Rule 433

This offering summary does not contain all of the material information an investor should consider before investing in the securities. This offering summary is not for distribution in isolation and must be read together with the accompanying preliminary pricing supplement and the other documents referred to therein, which can be accessed via the link on the first page.