花旗集团美股招股说明书(2025-09-15版)

The information in this preliminary pricing supplement is not complete and may be changed. A registration statement relating to these securities has been filed with the Securities andExchange Commission. This preliminary pricing supplement and the accompanying product supplement, underlying supplement, prospectus supplement and prospectus are not an offerto sell these securities, nor are they soliciting an offer to buy these securities, in any state where the offer or sale is not permitted.SUBJECT TO COMPLETION, DATED SEPTEMBER 15, 2025September, 2025 Medium-Term Senior Notes, Series NPricing Supplement No. 2025-USNCH28354Filed Pursuant to Rule 424(b)(2)Registration Statement Nos. 333-270327 and 333-270327-01 Citigroup Global Markets Holdings Autocallable Barrier Securities Linked to the Worst Performing of the Dow Jones Industrial AverageTMand the S&P 500®Index Due ▪The securities offer the potential for automatic early redemption at a premium following the first valuation date (other than the final valuation date) on which the closing value of the worstperforming underlying on that valuation date is greater than or equal to its initial underlying value. If the securities are not automatically redeemed prior to maturity, the securities will nolonger offer the opportunity to receive a premium, but instead, at maturity, will provide for (i) the opportunity to participate in any appreciation of the worst performing underlying from itsinitial underlying value at the upside participation rate specified below and (ii) contingent repayment of the stated principal amount at maturity if the worst performing underlying depreciates,but onlyso long as its final underlying value is greater than or equal to its final barrier value specified below.However, if the securities are not automatically redeemed prior tomaturity and the final underlying value of the worst performing underlying on the final valuation date is less than its final barrier value, you will lose 1% of the stated principalamount of your securities for every 1% by which its final underlying value is less than its initial underlying value. You will be subject to risks associated witheachof the underlyings and will be negatively affected by adverse movements inany oneof the underlyings. Although you will have downsideexposure to the worst performing underlying on the final valuation date, you will not receive dividends with respect to any underlying. ▪Investors in the securities must be willing to accept (i) an investment that may have limited or no liquidity and (ii) the risk of not receiving any payments due under the securities if we andCitigroup Inc. default on our obligations.All payments on the securities are subject to the credit risk of Citigroup Global Markets Holdings Inc. and Citigroup Inc. Issuer:Citigroup Global Markets Holdings Inc., a wholly owned subsidiary of Citigroup Inc. September 28, 2026, September 27, 2027 and September 25, 2030 (the “final valuation date”), each subject to postponement if suchdate is not a scheduled trading day or certain market disruption events occur Automatic early redemption:If, on any valuation date prior to the final valuation date, the closing value of the worst performing underlying on that valuation date isgreater than or equal to its initial underlying value, the securities will be automatically redeemed on the third business day immediatelyfollowing that valuation date for an amount in cash per security equal to $1,000 plus the premium applicable to that valuation date. If thesecurities are automatically redeemed following any valuation date prior to the final valuation date, they will cease to be outstanding andyou will not receive the premium applicable to any later valuation date or have the opportunity to participate in any appreciation of anyunderlying. If the securities are not automatically redeemed prior to maturity, you will receive at maturity for each security you then hold:■ If the final underlying value of the worst performing underlying on the final valuation date isgreater thanits initial underlyingvalue: $1,000 + the return amount■If the final underlying value of the worst performing underlying on the final valuation date isless than or equal toits initialunderlying value butgreater than or equal toits final barrier value: $1,000■If the final underlying value of the worst performing underlying on the final valuation date isless thanits final barrier value:$1,000 + ($1,000 × the underlying return of the worst performing underlying on the final valuation date) If the securities are not automatically redeemed prior to maturity and the final underlying value of the worst performingunderlying on the final valuation date is less than its final barrier value, you will receive significantly less than the statedprincipal amount of your securities, and possibly nothing, at maturity. $1,000 × the underlying return of the worst performing underlying × the upside participation rate (1) Ci