花旗集团美股招股说明书(2026-03-06版)

The securities discussed by this product summarysupplement are unsecured debt securities issued byCitigroup Global Markets Holdings Inc. andguaranteed by Citigroup Inc. Thus all payments on thesecurities are subject to the credit risk of CitigroupGlobal Markets Holdings Inc. and Citigroup Inc. The information in this product summary supplement is not complete and may bechanged. This product summary supplement is not an offer to sell these securitiesand it is not soliciting an offer to buy the securities in any jurisdiction where the offeror sale is not permitted. Neither the Securities and Exchange Commission nor any state securitiescommission has approved or disapproved of the securities or determined that thisproduct summary supplement and the accompanying product supplement,prospectus supplement and prospectus are truthful or complete. Any representationto the contrary is a criminal offense. The securities are not bank deposits and are notinsured or guaranteed by the Federal DepositInsurance Corporation or any other governmentalagency, nor are they obligations of, or guaranteed by, abank. The product supplement, prospectus supplement and prospectus referenced belowcontain certain general terms of Enhanced Barrier Digital Plus Securities. The specificterms of any offering of Enhanced Barrier Digital Plus Securities will be set forth in apricing supplement for that offering, which may add, update or modify any informationin this document or the product supplement, prospectus supplement or prospectus. Ifany information in the applicable pricing supplement is inconsistent with the otheroffering documents, including this document, you should rely on the information inthat pricing supplement. You should read the applicable pricing supplement togetherwith the product supplement, prospectus supplement and prospectus before makinga decision to invest in any Enhanced Barrier Digital Plus Security. You may accessthe product supplement, prospectus supplement and prospectus on the SEC websiteatwww.sec.govas follows: Investing in the securities involves risksnot associated with an investment inconventional debt securities. See “Keyrisks associated with Enhanced BarrierDigital Plus Securities” beginning onpage 3 and the accompanying ProductSupplement. The securities will not be listed on any securities exchange. Product Supplement No. ES-01-11 dated February 25, 2026 Prospectus Supplement and Prospectus each dated February 25, 2026