花旗集团美股招股说明书(2025-10-29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 28, 2025November, 2025 Medium-Term Senior Notes, Series NPricing Supplement No. 2025-USNCH29173Filed Pursuant to Rule 424(b)(2)Registration Statement Nos. 333-270327 and 333-270327-01 Citigroup Global Markets Holdings ▪The securities offer the potential for automatic early redemption at a premium following the first valuation date (other than the final valuation date) on which the closing value of the worstperforming underlying on that valuation date is greater than or equal to its autocall barrier value. If the securities are not automatically redeemed prior to maturity, the securities will providefor (i) repayment of the stated principal amountplusa premium at maturity if the final underlying value of the worst performing underlying on the final valuation date is greater than or equalto its autocall barrier value or (ii) repayment of the stated principal amount at maturity, with no premium, if the final underlying value of the worst performing underlying on the final valuationdate is less than its autocall barrier value but greater than or equal to its final barrier value specified below.However, if the securities are not automatically redeemed prior to maturityand the final underlying value of the worst performing underlying on the final valuation date is less than its final barrier value, you will lose 1% of the stated principal amountof your securities for every 1% by which its final underlying value is less than its initial underlying value.▪ 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 on the final valuation date, 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 Valuation dates:November 17, 2026, February 16, 2027, May 14, 2027, August 16, 2027, November 15, 2027, February 14, 2028, May 15, 2028, August 14, 2028,November 14, 2028, February 14, 2029, May 14, 2029, August 14, 2029, November 14, 2029, February 14, 2030, May 14, 2030, August 14, 2030and November 14, 2030 (the “final valuation date”), each subject to postponement if such date is not a scheduled trading day or certain marketdisruption events occur Automatic early redemption:If, on any valuation date prior to the final valuation date, the closing value of the worst performing underlying on that valuation date is greater thanor equal to its autocall barrier value, the securities will be automatically redeemed on the third business day immediately following that valuationdate for an amount in cash per security equal to $1,000 plus the premium applicable to that valuation date. If the securities are automaticallyredeemed following any valuation date prior to the final valuation date, they will cease to be outstanding and you will not receive the premiumapplicable to any later valuation date. Payment at maturity:If the securities are not automatically redeemed prior to maturity, you will receive at maturity for each security you then hold:■ If the final underlying value of the worst performing underlying on the final valuation date isgreater than or equal toits autocall barriervalue: $1,000 + the premium applicable to the final valuation date■If the final underlying value of the worst performing underlying on the final valuation date isless thanits autocall barrier value butgreaterthan or equal toits final barrier value: $1,000■If the final underlying value of the worst performing underlying on the final valuation date isless thanits final barrier value:$1,000 + ($1,000 × the underlying return of the worst performing underlying on the final valuation date) If the securities are not automatically redeemed prior to maturity and the final underlying value of the worst performing underlying on thefinal valuation date is less than its final barrier value, you will receive significantly less than the stated principal amount of yoursecurities, and possibly nothing, at maturity. The securities will not be listed on a