花旗集团美股招股说明书(2025-06-26版)

Table of Contents EXPLANATORY NOTE On April25, 2025, a prospectus supplement was filed under Rule 424(b)(8) for “Floating Rate Senior Notes due 2029” and included thereto an attachedfee table as Exhibit 107. That fee table incorrectly showed fees of $261,572 due in connection with “4.113% Fixed Rate / Floating Rate Senior Notesdue 2036.” This prospectus supplement, also filed under Rule 424(b)(8), includes an updated fee table attached hereto as Exhibit 107 which shows thecorrect calculation of fees due for the “Floating Rate Senior Notes due 2029.” This fee table will result in a fee offset of $87,191.10 to be claimedagainst future payments due to the Securities and Exchange Commission. This prospectus supplement is being filed only for explanatory purposes underRule 424(b)(8) and therefore no fees are due in connection herewith. Table of Contents The notes will mature on April29, 2029. The notes will bear interest from, and including, the date of issuance of the notes at an annual rate equal toEURIBOR (as defined on page33 of the accompanying prospectus) plus 1.100%, payable quarterly in arrears on each January29, April29, July29 andOctober29, beginning on July29, 2025. Citigroup may redeem the notes in whole, but not in part, on or after April29, 2028 at a redemption price equal to 100% of the principal amount of thenotes being redeemed and accrued and unpaid interest thereon to, but excluding, the date of redemption. In addition, Citigroup may redeem the notes prior tomaturity if changes involving United States taxation occur which could require Citigroup to pay additional amounts, as described under “Description of DebtSecurities—Payment of Additional Amounts” and “—Redemption for Tax Purposes” in the accompanying prospectus. The notes are being offered globally for sale in the United States, Europe, Asia and elsewhere where it is lawful to make such offers. Application will bemade to list the notes on the regulated market of the Luxembourg Stock Exchange, but Citigroup cannot assure you that the notes will be approved for listingand is not required to maintain this listing. See “Description of Notes—Listing” below. Investing in the notes involves a number of risks. See the “Risk Factors” section beginning on page 8 of the accompanying prospectus, wherespecific risks associated with the notes are described, and the factors listed and described under “Risk Factors” in our annual report onForm10-Kforthe year ended December31, 2024, along with the other information in, or incorporated by reference in, this prospectus supplement and theaccompanying prospectus before you make your investment decision. Neither the Securities and Exchange Commission nor any state securities commission nor the Luxembourg Stock Exchange has approved or disapprovedof these notes or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is acriminal offense. Public Offering Price Underwriting Discount Proceeds to Citigroup (before expenses) The notes are not deposits or savings accounts but are unsecured debt obligations of Citigroup. The notes are not insured by the Federal Deposit InsuranceCorporation or by any other governmental agency or instrumentality. Citigroup BarclaysCapital One SecuritiesEmirates NBD CapitalINGMizuhoNATIXISPNC Capital Markets LLCSMBCWestpac Banking Corporation ANZ SecuritiesBBVADeutsche BankErste GroupIMI – Intesa SanpaoloMUFGNomuraRBC Capital MarketsSociété Générale Corporate& Investment Banking ABN AMROCommonwealth Bank of AustraliaNational Bank of Canada Financial MarketsStandard Chartered BankApril22, 2025 CIBC Capital MarketsMacquarie CapitalSantanderUBS Investment Bank Table of Contents TABLE OF CONTENTS Prospectus Supplement Forward-Looking StatementsDescription of NotesUnderwritingConflicts of InterestLegal Opinions Prospectus The Luxembourg Stock Exchange takes no responsibility for the contents of this document, makes no representation as to its accuracy orcompleteness and expressly disclaims any liability whatsoever for any loss howsoever arising from or in reliance upon the whole or any part ofthe contents of this prospectus supplement and the accompanying prospectus. The distribution or possession of this prospectus supplement and the accompanying prospectus in or from certain jurisdictions may be restrictedby law. Persons into whose possession this prospectus supplement and the accompanying prospectus come are required by Citigroup and theunderwriters to inform themselves about, and to observe any such restrictions, and neither Citigroup nor any of the underwriters accepts any liability inrelation thereto. See “Underwriting.” Table of Contents In connection with this issue, Citigroup Global Markets Limited as stabilizing manager (or persons acting on behalf of the stabilizing manager)may over-allot notes (provided thatthe aggregate principal amount of notes allotted does not exceed 105% o