花旗集团美股招股说明书(2025-10-21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 20, 2025October, 2025 Medium-Term Senior Notes, Series NPricing Supplement No. 2025-USNCH29035Filed Pursuant to Rule 424(b)(2)Registration Statement Nos. 333-270327 and 333-270327-01 Citigroup Global Markets Holdings Inc. Market-Linked Securities Linked to the S&P 500 Futures Excess Return Index Due November 1, 2028 ▪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 guarantee the full repayment of principal at maturity. Instead, the securities offer the potential for a return at maturity based on theperformance of the underlying specified below from the initial underlying value to the final underlying value.▪ The underlying tracks futures contracts on the S&P 500®Index and is expected to underperform the total return performance of the S&P 500®Index because of an implicit financing cost.See “Summary Risk Factors” for more information.▪ If the underlying appreciates from the initial underlying value to the final underlying value, you will receive a positive return at maturity equal to that appreciationmultipliedby the upsideparticipation rate, subject to the maximum return at maturity specified below. However, if the underlying depreciates from the initial underlying value to the final underlying value, you willincur a loss at maturity equal to that depreciation, subject to the maximum loss at maturity. Even if the underlying appreciates from the initial underlying value to the final underlying value,so that you do receive a positive return at maturity, there is no assurance that your total return at maturity on the securities will compensate you for the effects of inflation or be as great asthe yield you could have achieved on a conventional debt security of ours of comparable maturity.▪ In exchange for the capped loss potential if the underlying depreciates, investors in the securities must be willing to (i) accept exposure to an index that is expected to underperform thetotal return performance of the S&P 500®Index, (ii) forgo any return on the securities in excess of the maximum return at maturity and (iii) forgo dividends with respect to the underlying.Ifthe underlying does not appreciate from the initial underlying value to the final underlying value, you will not receive any return on your investment in the securities, and youmay lose up to the maximum loss at maturity.▪ 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 underlying depreciates from the initial underlying value to the final underlying value, you will be exposed to that depreciation up tothe maximum loss at maturity. You should not invest in the securities unless you are willing and able to bear the risk of losing up to themaximum loss at maturity. The maximum return at maturity will be determined on the pricing date and will be at least $500.00 per security (at least 50.00% of the statedprincipal amount). The payment at maturity per security will not exceed the stated principal amount plus the maximum return at maturity. Maximum return at maturity: Maximum loss at maturity:$50.00 per security (5.00% of the stated principal amount). The maximum loss at maturity represents the maximum loss that may be realized atmaturity under the terms of the securities (that is, the maximum amount by which the stated payment at maturity may be less than the statedprincipal amount). If you sell the securities prior to maturity, or if we and Citigroup Inc. default on our obligations under the securities, you may incura greater loss on your investment. The securities will not be listed on any securities exchange Citigroup Global Markets Inc. (“CGMI”), an affiliate of the issuer, acting as principal (1) Citigroup Global Markets Holdings Inc. currently expects that the estimated value of the securities on the pricing date will be at least $923.00 per security, which will be less than the issue price. Theestimated value of the securities is based on CGMI’s p