花旗集团美股招股说明书(2025-10-07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 7, 2025October, 2025 Medium-Term Senior Notes, Series NPricing Supplement No. 2025-USNCH28774Filed Pursuant to Rule 424(b)(2)Registration Statement Nos. 333-270327 and 333-270327-01 Citigroup Global Markets Holdings Single Observation Equity Linked Securities Linked to the Worst Performing of the Nasdaq-100 Index®and 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. The securities offerperiodic coupon payments at an annualized rate that is generally higher than the yield on our conventional debt securities of the same maturity. In exchange for this higher yield, you mustbe willing to accept the risk that the value of what you receive at maturity may be significantly less than the stated principal amount of your securities, and may be zero (excluding the finalcoupon payment). The risk that you may incur a loss at maturity will depend solely on the performance of theworst performingof the underlyings specified below.▪ 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, you will not receive dividends with respect to any underlying or participate in any appreciation of 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. On each coupon payment date, the securities will pay a coupon equal to at least 3.175% of the stated principal amount of thesecurities (equivalent to a coupon rate of at least 6.35% per annum) (to be determined on the pricing date). If the final underlying value of the worst performing underlying is less than its final buffer value, which means that theworst performing underlying has depreciated from its initial underlying value by more than the buffer percentage, youwill lose more than 1% of the stated principal amount of your securities at maturity for every 1% by which thatdepreciation exceeds the buffer percentage. Accordingly, the lower the final underlying value of the worst performingunderlying, the less benefit you will receive from the buffer. (1) Citigroup Global Markets Holdings Inc. currently expects that the estimated value of the securities on the pricing date will be at least $940.00 per security, which will be less than theissue price. The estimated 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 ouraffiliates, nor is it an indication of the 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 theSecurities” in this pricing supplement. (2) CGMI will receive an underwriting fee of up to $1.50 for each security sold in this offering. The total underwriting fee and proceeds to issuer in the table above give effect to the actualtotal underwriting fee. For more information on the distribution of the securities, see “Supplemental Plan of Distribution” in this pricing supplement. In addition to the underwriting fee, CGMIand its affiliates may profit from expected hedging activity related to this offering, even if the value of the securities declines. See “Use of Proceeds and Hedging” in the accompanyingprospectus.(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, the underwriting 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 the accompanying product supplement, underlying supplement, prospectus supplement and prospectus are truthful or complete. Any representation to thecontrary is a criminal