花旗集团美股招股说明书(2026-04-22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 APRIL 21, 2026 April, 2026Medium-Term Senior Notes, Series NPricing Supplement No. 2026-USNCH[ ]Filed Pursuant to Rule 424(b)(2)Registration Statement Nos. 333-293732 and 333-293732-02 Citigroup Global Markets Holdings Barrier Securities Linked to the S&P 500 Futures 35% Edge Volatility 6% Decrement Index (USD) ER Due May 8, 2031 ▪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 repay a fixed amount of principal at maturity. Instead, the securities offer a payment at maturity that may be greater than, equal to orless than the stated principal amount, depending on the performance of the underlying specified below from the initial underlying value to the final underlying value.▪ The securities offer modified exposure to the performance of the underlying, with (i) the opportunity to participate in any appreciation of the underlying at the upside participation ratespecified below and (ii) contingent repayment of the stated principal amount at maturity if the underlying depreciates,but onlyso long as the final underlying value is greater than or equalto the final barrier value specified below. In exchange for these features, investors in the securities must be willing to forgo any dividends with respect to the underlying. In addition,investors in the securities must be willing to accept full downside exposure to the depreciation of the underlying if the final underlying value is less than the final barrier value.If the finalunderlying value is less than the final barrier value, you will lose 1% of the stated principal amount of your securities for every 1% by which the final underlying value is lessthan the initial underlying value. You may lose your entire investment in the securities.▪ The underlying is highly risky because it may reflect highly leveraged exposure to any decline in the S&P 500 Futures Excess Return Index. The S&P 500 Futures ExcessReturn Index tracks futures contracts on the S&P 500®Index and is likely to underperform the S&P 500®Index because of an implicit financing cost. In addition, the underlyingis subject to a decrement of 6% per annum, which will be a significant drag on its performance. You should carefully review the section “Summary Risk Factors—Risksrelating to the S&P 500 Futures 35% Edge Volatility 6% Decrement Index (USD) ER” in this pricing supplement.▪ 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 final underlying value is less than the final barrier value, you will receive significantly less than the stated principal amount of yoursecurities, and possibly nothing, 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 $850.00 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)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.In addition, CGMI will pay to one or more electronic platform providers a fee of $1.50 for each security sold in this offering where related selected dealers and/or custodians implement or utilize suchproviders. Investing in the securities involves risks not associated with an investment in conventional debt securities. See “Summary Risk Factors” begin