花旗集团美股招股说明书(2025-09-25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 25, 2025September, 2025 Medium-Term Senior Notes, Series NPricing Supplement No. 2025-USNCH28530Filed 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 S&P 500®Index Due December 31, 2026▪ 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 the underlying specified below from the initial underlying value to the final underlying value.▪ The securities offer modified exposure to the performance of the underlying, with (i) the opportunity to participate in a limited range of potential appreciation of the underlying at theparticipation rate specified below, (ii) the opportunity for a positive return at maturity if the underlying depreciates within a limited range (not more than the buffer percentage specifiedbelow) based on the absolute value of that depreciation and (iii) a limited buffer against any depreciation of the underlying in excess of the buffer percentage. In exchange for thesefeatures, investors in the securities must be willing to forgo any appreciation of the underlying in excess of the maximum upside return specified below and must be willing to forgo anydividends with respect to the underlying. In addition, investors in the securities must be willing to accept downside exposure to any depreciation of the underlying in excess of the bufferpercentage specified below.If the underlying depreciates by more than the buffer percentage from the initial underlying value to the final underlying value, you will lose 1% ofthe stated principal amount of your securities for every 1% by which that depreciation exceeds the buffer percentage.▪ In order to obtain the modified exposure to the underlying that the securities provide, investors must be willing to accept (i) an investment that may have limited or no liquidity and (ii) therisk 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 credit risk of CitigroupGlobal Markets Holdings Inc. and Citigroup Inc. You will receive at maturity for each security you then hold:■ If the final underlying value isgreater than or equal tothe initial underlying value:$1,000 + the upside return amount, subject to the maximum upside return■If the final underlying value isless thanthe initial underlying value butgreater than or equal tothe final buffer value:$1,000 + the absolute return amount■If the final underlying value isless thanthe final buffer value:$1,000 + [$1,000 × (the underlying return + the buffer percentage)] $118.50 per security (11.85% of the stated principal amount). The payment at maturity per security will not exceed the stated principal amount plusthe maximum upside return. The securities will not be listed on any securities exchange Citigroup Global Markets Inc. (“CGMI”), an affiliate of the issuer, acting as principal (1) Citigroup Global Markets Holdings Inc. currently expects that the estimated value of the securities on the pricing date will be at least $919.50 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. (4) 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 Investing in the securities involves risks not associated with an investment in conventional debt securities. See “Summary Risk Factors” beginning onpage PS-5.Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of the securities or determined that