花旗集团美股招股说明书(2025-10-09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 8, 2025October, 2025 Medium-Term Senior Notes, Series NPricing Supplement No. 2025-USNCH28821Filed Pursuant to Rule 424(b)(2)Registration Statement Nos. 333-270327 and 333-270327-01 Citigroup Global Markets Holdings Autocallable Equity Linked Securities Linked to the Worst Performing of the Nasdaq-100 Index®and the S&P 500®Index Due April ▪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 risks that (i) 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 thefinal coupon payment), and (ii) the securities may be automatically called for redemption prior to maturity beginning on the first potential autocall date specified below. Each of these riskswill 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. KEY TERMS Citigroup Global Markets Holdings Inc., a wholly owned subsidiary of Citigroup Inc. All payments due on the securities are fully and unconditionally guaranteed by Citigroup Inc. Stated principal amount:$1,000 per securityPricing date:October 15, 2025Issue date:October 20, 2025 April 15, 2027, subject to postponement if such date is not a scheduled trading day or certain market disruption events occurUnless earlier redeemed, April 20, 2027 Coupon payments:On each coupon payment date, unless previously redeemed, the securities will pay a coupon equal to at least 0.6833% of thestated principal amount of the securities (equivalent to a coupon rate of approximately at least 8.20% per annum) (to bedetermined on the pricing date). Coupon payment dates:The 20th day of each calendar month beginning in November 2025. If any coupon payment date is not a business day, thepayment to be made on that coupon payment date will be made on the next succeeding business day with the same force andeffect as if made on that coupon payment date. No interest will accrue as a result of any delayed payment. If the securities are not automatically redeemed prior to maturity, you will receive at maturity for each security you then hold (inaddition to the final coupon payment): ■If the final underlying value of the worst performing underlying on the valuation date isgreater than or equal toits finalbarrier value: $1,000■If the final underlying value of the worst performing underlying on the valuation date isless thanits final barrier value:$1,000 + ($1,000 × the underlying return of the worst performing underlying on the valuation date) If the securities are not automatically redeemed prior to maturity and the final underlying value of the worst performingunderlying on the valuation date is less than its final barrier value, you will receive significantly less than the statedprincipal amount of your securities, and possibly nothing (other than the final coupon payment), at maturity. The securities will not be listed on any securities exchange Listing: (1) Citigroup Global Markets Holdings Inc. currently expects that the estimated value of the securities on the pricing date will be at least $948.00 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