瑞穗金融美股招股说明书(2025-06-26版)

Table of Contents The Information in this preliminary prospectus supplement and the accompanying prospectus is incompleteand subject to completion and amendment. This preliminary prospectus supplement and the accompanyingprospectus is not an offer to sell, nor does it seek an offer to buy, these securities in any jurisdiction where theoffer or sale is not permitted. SUBJECT TO COMPLETION, DATED JUNE 26, 2025PRELIMINARY PROSPECTUS SUPPLEMENT(To prospectus dated October 4, 2024) Mizuho Financial Group, Inc.% Senior Callable Fixed-to-Fixed Reset Rate Notes due 2031 U.S.$U.S.$% Senior Callable Fixed-to-Fixed Reset Rate Notes due 2036U.S.$Senior Callable Floating Rate Notes due 2031 Mizuho Financial Group, Inc., a joint stock corporation incorporated with limited liability under the laws of Japan (“MizuhoFinancial Group” or the “Issuer”), will issue an aggregate principal amount of $of senior callable fixed-to-fixed reset ratenotes due July, 2031 (the “6-year Notes”) and an aggregate principal amount of $of senior callable fixed-to-fixed resetrate notes due July, 2036 (the “11-year Notes” and, together with the 6-year Notes, the “Fixed-to-Fixed Reset Rate Notes”). The 6-year Notes will bear interest (i) from (and including) July, 2025 to (but excluding) July, 2030 (the “6-year Notes ResetDate”), at the fixed rate of% per annum, payable semi-annually in arrears on Januaryand Julyof each year, with the firstinterest payment to be made on January, 2026, and (ii) from (and including) the 6-year Notes Reset Date to (but excluding) thematurity date, at a fixed per annum rate equal to the applicable U.S. Treasury Rate (as defined below) as determined by theCalculation Agent (as defined below) on the 6-year Notes Reset Determination Date (as defined below) as described under“Description of the Notes—Fixed-to-Fixed Reset Rate Notes—Determination of the U.S. Treasury Rate,” plus%, payablesemi-annually in arrears on January, 2031 and July, 2031. The 6-year Notes will mature on July, 2031. The 11-year Notes will bear interest (i) from (and including) July, 2025 to (but excluding) July, 2035 (the “11-year NotesReset Date”), at the fixed rate of% per annum, payable semi-annually in arrears on Januaryand Julyof each year, withthe first interest payment to be made on January, 2026, and (ii) from (and including) the 11-year Notes Reset Date to (butexcluding) the maturity date, at a fixed per annum rate equal to the applicable U.S. Treasury Rate as determined by the CalculationAgent on the 11-year Notes Reset Determination Date (as defined below) as described under “Description of the Notes—Fixed-to-Fixed Reset Rate Notes—Determination of the U.S. Treasury Rate,” plus%, payable semi-annually in arrears on January,2036 and July, 2036. The 11-year Notes will mature on July, 2036. Mizuho Financial Group will also issue an aggregate principal amount of $of senior callable floating rate notes due July, 2031 (the “Floating Rate Notes” and, together with the Fixed-to-Fixed Reset Rate Notes, the “Notes”). The Floating Rate Noteswill bear interest commencing July, 2025 at a floating per annum rate equal to Compounded Daily SOFR (as defined below),plus%, determined as described under “Description of the Notes—Floating Rate Notes,” payable quarterly in arrears onJanuary, April, Julyand Octoberof each year, beginning on October, 2025, subject to adjustments. The FloatingRate Notes will mature on July, 2031. Mizuho Financial Group may redeem, at its option, each series of the Notes, in whole, but not in part, on the date that is one yearprior to the maturity date of such series of Notes, at the applicable redemption price, subject to certain conditions. See “Descriptionof Notes—Optional Redemption.” In addition, Mizuho Financial Group may at its option redeem the Notes of each series, in whole,but not in part, upon the occurrence of certain changes in Japanese tax law, subject to certain conditions. See “Description of theNotes—Optional Tax Redemption.” Each series of the Notes will not be subject to any sinking fund. The Notes will be representedby one or more global notes deposited with a custodian for and registered in the name of a nominee of The Depository TrustCompany (“DTC”), as depositary. Beneficial interests in the Notes will be shown on, and transfers thereof will be effected onlythrough, records maintained by DTC and its direct and indirect participants, including Euroclear Bank SA/NV (“Euroclear”), andClearstream Banking S.A. (“Clearstream”). The Notes will be issued only in registered form in minimum denominations of$200,000 and integral multiples of $1,000 in excess thereof. The net proceeds from the issuance and sale of each series of the Notes will be used to make a loan to Mizuho Bank (as definedbelow), which intends to utilize such funds for its general corporate purposes.See “Use of Proceeds.” Each series of the Notes is intended to qualify as external total loss-absorbing capacity (“TLAC”) debt under the Japane