花旗集团美股招股说明书(2025-10-16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 OCTOBER 15, 2025October, 2025 Medium-Term Senior Notes, Series NPricing Supplement No. 2025-USNCH28975Filed Pursuant to Rule 424(b)(2)Registration Statement Nos. 333-270327 and 333-270327-01 Citigroup Global Markets Holdings Callable Contingent Coupon Equity Linked Securities Linked to the Russell 2000®Index Due October 19, 2029 ▪The securities offered by this pricing supplement are unsecured debt securities issued by Citigroup Global Markets Holdings Inc. and guaranteed by Citigroup Inc. The securities offer thepotential for periodic contingent coupon payments at an annualized rate that, if all are paid, would produce a yield that is generally higher than the yield on our conventional debt securitiesof the same maturity. In exchange for this higher potential yield, you must be willing to accept the risks that (i) your actual yield may be lower than the yield on our conventional debtsecurities of the same maturity because you may not receive one or more, or any, contingent coupon payments, and (ii) the value of what you receive at maturity may be significantly lessthan the stated principal amount of your securities, and may be zero. Each of these risks will depend on the performance of the underlying specified below.▪ We have the right to call the securities for mandatory redemption on any potential redemption date specified below. Although you will have downside exposure to the underlying, you willnot receive dividends with respect to the underlying or participate in any appreciation of the 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. Payment at maturity:If the securities are not redeemed prior to maturity, you will receive at maturity for each security you then hold (in addition to thefinal contingent coupon payment, if applicable):■If the final underlying value isgreater than or equal tothe final barrier value: $1,000■If the final underlying value isless thanthe final barrier value:$1,000 + ($1,000 × the underlying return) If the securities are not redeemed prior to maturity and the final underlying value is less than the final barrier value, youwill receive significantly less than the stated principal amount of your securities, and possibly nothing, at maturity, andyou will not receive any contingent coupon payment at maturity. (1) Citigroup Global Markets Holdings Inc. currently expects that the estimated value of the securities on the pricing date will be at least $936.50 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 $2.50 for each security sold in this offering. The total underwriting fee and proceeds to issuer in the table above give effect to the actual total underwritingfee.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.(3) 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, theunderwriting fee is variable. Investing in the securities involves risks not associated with an investment in conventional debt securities. See “Summary Risk Factors” beginning onpage PS-6. 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, underlying supplement, prospectus supplement and prospectus are truthful