花旗集团美股招股说明书(2025-10-01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, prospectus supplement and prospectus are not an offer to 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 OCTOBER 1, 2025October, 2025 Medium-Term Senior Notes, Series NPricing Supplement No. 2025-USNCH28710Filed Pursuant to Rule 424(b)(2)Registration Statement Nos. 333-270327 and 333-270327-01 Citigroup Global Markets Holdings Buffer Securities Linked to Intel Corporation Due October 15, 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 the upsideparticipation rate specified below and (ii) a limited buffer against any depreciation of the underlying as described below. In exchange for these features, investors in the securities must bewilling to forgo any appreciation of the underlying in excess of the maximum return at maturity specified below and must be willing to forgo any dividends with respect to the underlying. Inaddition, investors in the securities must be willing to accept downside exposure to any depreciation of the underlying in excess of the buffer percentage specified below.If the underlyingdepreciates by more than the buffer percentage from the initial underlying value to the 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 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. If the final underlying value is less than the final buffer value, which means that the underlying has depreciated from the initialunderlying value by more than the buffer percentage, you will lose 1% of the stated principal amount of your securities at maturity forevery 1% by which that depreciation exceeds the buffer percentage. (i) The final underlying valueminusthe initial underlying value,divided by(ii) the initial underlying value (3)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 fromexpected hedging activity related to this offering, even if the value of the securities declines. See “Use of Proceeds and Hedging” in the accompanying prospectus. Investing in the securities involves risks not associated with an investment in conventional debt securities. See “Summary Risk Factors” beginning on 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 theaccompanying product 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, prospectus supplement and prospectus, which can be accessed via the hyperlinks below: 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, orguaranteed by, a bank. Additional Information General.The terms of the securities are set forth in the accompanying product supplement, prospectus supplement and prospectus, assupplemented 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 informationabout how the closing value of the underlying will be determined and about adjustments that may be made t