花旗集团美股招股说明书(2025-09-29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 26, 2025October, 2025 Medium-Term Senior Notes, Series NPricing Supplement No. 2025-USNCH28597Filed Pursuant to Rule 424(b)(2)Registration Statement Nos. 333-270327 and 333-270327-01 Citigroup Global Markets Holdings Dual Directional Buffer Securities Linked to the Worst Performing of the Dow Jones Industrial AverageTMand the Russell 2000®Index ▪The securities offered by this pricing supplement are unsecured debt securities issued by Citigroup Global Markets Holdings Inc. and guaranteed by Citigroup Inc. Unlike conventional debtsecurities, the securities do not pay interest and do not repay a fixed amount of principal at maturity. Instead, the securities offer a payment at maturity that may be greater than, equal to orless than the stated principal amount, depending on the performance of theworst performingof the underlyings specified below from its initial underlying value to its final underlyingvalue.▪ The securities offer modified exposure to the performance of the worst performing underlying, with (i) the opportunity to participate in a limited range of potential appreciation of the worstperforming underlying at the participation rate specified below, (ii) the opportunity for a positive return at maturity if the worst performing underlying depreciates within a limited range (notmore than the buffer percentage specified below) equal to the absolute value of that depreciationmultiplied bythe participation rate and (iii) a limited buffer against any depreciation of theworst performing underlying in excess of the buffer percentage. In exchange for these features, investors in the securities must be willing to forgo any appreciation of the worst performingunderlying in excess of the maximum upside return specified below and must be willing to forgo any dividends with respect to any underlying. In addition, investors in the securities must bewilling to accept downside exposure to any depreciation of the worst performing underlying in excess of the buffer percentage specified below.If the worst performing underlyingdepreciates by more than the buffer percentage from its initial underlying value to its final underlying value, you will lose 1% of the stated principal amount of your securitiesfor every 1% by which that depreciation exceeds the buffer percentage.▪ In order to obtain the modified exposure to the worst performing underlying that the securities provide, investors must be willing to accept (i) an investment that may have limited or noliquidity and (ii) the risk of not receiving any amount due under the securities if we and Citigroup Inc. default on our obligations.All payments on the securities are subject to the creditrisk of Citigroup Global Markets Holdings Inc. and Citigroup Inc. You will receive at maturity for each security you then hold:■ If the final underlying value of the worst performing underlying isgreater than or equal toits initial underlying value:$1,000 + the upside return amount, subject to the maximum upside return■If the final underlying value of the worst performing underlying isless thanits initial underlying value butgreater than or equal toits finalbuffer value:$1,000 + the absolute return amount■If the final underlying value of the worst performing underlying isless thanits final buffer value:$1,000 + [$1,000 × (the underlying return of the worst performing underlying + the buffer percentage)] If the final underlying value of the worst performing underlying is less than its final buffer value, which means that the worst performingunderlying has depreciated from its initial underlying value by more than the buffer percentage, you will lose 1% of the stated principalamount of your securities at maturity for every 1% by which that depreciation exceeds the buffer percentage. (1) Citigroup Global Markets Holdings Inc. currently expects that the estimated value of the securities on the pricing date will be at least $915.50 per security, which will be less than the issue price. Theestimated 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 ofthe 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 $24.00 for each security