Mizuho files indenture for perpetual subordinated debt

Mizuho Financial Group, Inc. added subordinated debt documentation and legal opinions to its existing Form F-3 shelf via incorporation by reference.

Available on EDGAR 09/14/2026 - 11:25 AM EDT Accepted by SEC EDGAR 09/14/2026 - 11:25 AM EDT Learn about SEC filing dates

Rhea-AI Filing Summary

MIZUHO FINANCIAL GROUP INC (MFG) furnished a report providing documentation for potential future issuances of subordinated securities under its existing shelf Registration Statement on Form F-3 (File No. 333-282497). The report includes a Perpetual Subordinated Indenture with The Bank of New York Mellon and a form of Fixed Rate Resetting Perpetual Subordinated Security.

The report also provides legal opinions and related consents from Nagashima Ohno & Tsunematsu and Simpson Thacher & Bartlett LLP, which are incorporated by reference into the F-3 prospectus effective from the date of this report, to the extent not superseded by later documents.

Key Terms

Perpetual Subordinated Indenture, Fixed Rate Resetting Perpetual Subordinated Security, Registration Statement on Form F-3, incorporated by reference

4 terms

Perpetual Subordinated Indenture financial

"Perpetual Subordinated Indenture dated September 14, 2026 between Mizuho Financial Group, Inc."

Fixed Rate Resetting Perpetual Subordinated Security financial

"Form of Fixed Rate Resetting Perpetual Subordinated Security"

Registration Statement on Form F-3 regulatory

"prospectus forming a part of Mizuho Financial Group, Inc.’s Registration Statement on Form F-3"

A registration statement on Form F-3 is a streamlined filing used by eligible foreign companies to register securities for sale in the U.S., often as a “shelf” that lets them offer shares quickly when market conditions are right. For investors it matters because it signals that the company can raise capital on short notice—potentially increasing liquidity but also the risk of share dilution if new stock is issued—similar to a company keeping a pre-approved credit line ready to use.

incorporated by reference regulatory

"shall be deemed to be incorporated by reference into the prospectus"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What is the main purpose of MFG's September 2026 Form 6-K?

It furnishes documentation for perpetual subordinated securities, including an indenture and security form, and incorporates these materials and related legal opinions by reference into Mizuho Financial Group, Inc.’s existing Form F-3 (File No. 333-282497) shelf registration.

What new agreement did MFG report in this 6-K?

Mizuho Financial Group, Inc. reported a Perpetual Subordinated Indenture dated September 14, 2026, entered into with The Bank of New York Mellon, which provides the contractual framework for potential future perpetual subordinated securities.

What type of security is described in MFG's new exhibits?

The exhibits include a Form of Fixed Rate Resetting Perpetual Subordinated Security, describing the structure of perpetual subordinated instruments whose interest rate can reset, to be issued under the newly filed perpetual subordinated indenture.

Which legal opinions support MFG’s subordinated securities documentation?

Legal opinions are provided by Nagashima Ohno & Tsunematsu and Simpson Thacher & Bartlett LLP. Their opinions, along with their consents, are included as exhibits and are incorporated by reference into the existing Form F-3 prospectus.

How does this 6-K affect MFG's existing Form F-3 shelf registration?

The information and exhibits in this report are deemed incorporated by reference into the prospectus forming part of Mizuho Financial Group, Inc.’s Form F-3 (File No. 333-282497), and become part of that prospectus from the date this report is furnished.

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of September 2026

Commission File Number 001-33098

Mizuho Financial Group, Inc.

(Translation of registrant’s name into English)

5-5, Otemachi 1-chome

Chiyoda-ku, Tokyo 100-8176

Japan

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F. Form 20-F ☒ Form 40-F ☐

Indicate by check mark whether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934. Yes ☐ No ☒

If “Yes” is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b): 82-    .

The information and exhibits set forth in this Form 6-K shall be deemed to be incorporated by reference into the prospectus forming a part of Mizuho Financial Group, Inc.’s Registration Statement on Form F-3 (File No. 333-282497) and to be a part of such prospectus from the date on which this report is furnished, to the extent not superseded by documents or reports subsequently filed or furnished.

EXHIBIT INDEX

Exhibit		Description
4.1		Perpetual Subordinated Indenture dated September 14, 2026 between Mizuho Financial Group, Inc. and The Bank of New York Mellon
4.2		Form of Fixed Rate Resetting Perpetual Subordinated Security
5.1		Opinion of Nagashima Ohno & Tsunematsu
5.2		Opinion of Simpson Thacher & Bartlett LLP
23.1		Consent of Nagashima Ohno & Tsunematsu (included in exhibit 5.1)
23.2		Consent of Simpson Thacher & Bartlett LLP (included in exhibit 5.2)

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Date:		September 14, 2026
Mizuho Financial Group, Inc.
By:		/s/ Makoto Samejima
Name:		Makoto Samejima
Title:		Senior Managing Corporate Executive / Group Chief Financial Officer

Filing Exhibits & Attachments

4 documents

Other Documents

• EX-4.1 PERPETUAL SUBORDINATED INDENTURE 578.0 KB
• EX-4.2 FORM OF FIXED RATE RESETTING PERPETUAL SUBORDINATED SECURITY 84.9 KB
• EX-5.1 OPINION OF NAGASHIMA OHNO & TSUNEMATSU 22.9 KB
• EX-5.2 OPINION OF SIMPSON THACHER & BARTLETT LLP 10.4 KB