三井住友金融美股招股说明书(2026-02-24版)

Table of Contents Filed Pursuant to Rule 424(b)(5)Registration No. 333-276219 The information in this preliminary prospectus supplement and the accompanying prospectus is not complete and may be changed. This preliminaryprospectus supplement and the accompanying prospectus are not an offer to sell these securities and are not soliciting an offer to buy these securities in anyjurisdiction where the offer or sale is not permitted. PRELIMINARY PROSPECTUS SUPPLEMENT(To prospectus dated January11, 2024) Sumitomo Mitsui Financial Group, Inc.(incorporated under the laws of Japan with limited liability) Subordinated Callable Fixed-to-Fixed Rate Notes We expect to issue an aggregate principal amount of $of subordinated callable fixed-to-fixed rate notes due,, or the notes. The notes will bear interest (i)fromand including, 2026 to but excluding, 20(the “reset date”) at a fixed rate of%per annum, payable semiannually in arrears onandof each year,beginning on, 2026, and (ii)from and including the reset date to but excluding the maturity date, at a fixedper annumrate equal to the sum of the U.S. Treasury Rate (as definedherein) as determined by the Calculation Agent (as defined herein) on the reset determination date (as defined herein),plusa margin of%per annum, payable semiannually in arrearsonandof each year, beginning on, 20. We may, at our option, redeem the notes in whole, but not in part, (i)on the reset date, as described under “Description of the Notes—Optional Redemption” or (ii)upon theoccurrence of certain changes in Japanese tax law or certain changes in Japanese regulatory capital requirements, as described under “Description of the Notes—Redemption for TaxationReasons” and “Description of the Notes—Redemption for Regulatory Reasons,” respectively. The notes will be our direct and unsecured obligations and will at all times rankpari passuandwithout any preference among themselves and at least equally and ratably with all of our indebtedness that is subordinated to our senior indebtedness and is in priority to all of our perpetualsubordinated indebtedness, as described herein. The notes contain non-viability loss absorption provisions, pursuant to which, if a Non-Viability Event (as defined herein) occurs, the full principal amount of the notes will bepermanently written down to zero, the notes will be cancelled and the holders of the notes will be deemed to have irrevocably waived their right to claim or receive any payment of principalof or interest on the notes (including additional amounts with respect thereto, if any), except for any payments of principal or interest (including additional amounts with respect thereto, ifany) that have become due and payable prior to the occurrence of the Non-Viability Event, as described further herein under “Description of the Notes—Write-Down upon a Non-ViabilityEvent.” Unless previously redeemed or otherwise cancelled, and provided that a Non-Viability Event has not occurred, the notes will mature on,. The notes will be issued onlyin registered form in denominations of $2,000 and integral multiples of $1,000 in excess thereof and will not be subject to a sinking fund. We have made an application to the Luxembourg Stock Exchange to list the notes on the official list of the Luxembourg Stock Exchange and for such notes to be admitted to tradingon the Luxembourg Stock Exchange’s Euro MTF Market. The Luxembourg Stock Exchange’s Euro MTF Market is not a regulated market for the purposes of Directive 2014/65/EU. Thisprospectus supplement with the accompanying prospectus constitutes a prospectus for purposes of Part IV of the Luxembourg law on prospectuses for securities dated July16, 2019. Investing in the notes involves risks. You should carefully consider the risk factors set forth in “Item 3. Key Information—Risk Factors” of our most recent annual report onForm 20-F filed with the U.S. Securities and Exchange Commission, or the SEC, and in the “Risk Factors” section beginning on page S-8 of this prospectus supplement beforemaking any decision to invest in the notes. Public offering price(1) Underwriting commissions(2) Proceeds, before expenses, to SMFG(1) (1)Plus accrued interest from, 2026, if settlement occurs after that date.(2)For additional underwriting compensation information, see “Underwriting (Conflicts of Interest).” Neither the SEC nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus supplementor the related prospectus. Any representation to the contrary is a criminal offense. The notes will be represented by one or more global certificates deposited with a custodian for, and registered in the name of a nominee of, The Depository Trust Company, or DTC.Beneficial interests in these global certificates will be shown on, and transfers thereof will be effected through, records maintained by DTC and its direct and indirect participants, includingEuroclear B