Mizuho reports 8.8% passive stake in M3-Brigade Acquisition V Corp. (MBAV)

Rhea-AI Filing Summary

Mizuho Financial Group, Inc., a Japan-based parent holding company, has filed a Schedule 13G reporting a significant passive ownership position in M3-Brigade Acquisition V Corp. common shares.

Mizuho reports beneficial ownership of 2,543,600 common shares, representing 8.8% of the class, with the event date stated as December 31, 2025. Mizuho has sole voting and dispositive power over all 2,543,600 shares, with no shared voting or dispositive power.

The filing notes that Mizuho Financial Group, Inc., Mizuho Bank, Ltd. and Mizuho Americas LLC may be deemed indirect beneficial owners of these shares, which are directly held by their wholly owned subsidiary, Mizuho Securities USA LLC. Mizuho certifies the shares were acquired and are held in the ordinary course of business and not for the purpose of changing or influencing control of the issuer.

Insights

Equity ownership and governance analyst

Mizuho reports an 8.8% passive stake in M3-Brigade, signaling a sizable but non-control-oriented holding.

The filing shows Mizuho Financial Group beneficially owns 2,543,600 common shares of M3-Brigade Acquisition V Corp., equal to 8.8% of the class as of the December 31, 2025 event date. Voting and dispositive authority are described as solely held, with no shared power.

The shares are directly held by Mizuho Securities USA LLC, a wholly owned subsidiary, with Mizuho Financial Group, Mizuho Bank, Ltd. and Mizuho Americas LLC potentially deemed indirect beneficial owners. The Schedule 13G certification emphasizes ordinary-course acquisition and a stated lack of intent to influence control, positioning this as a passive institutional stake rather than an activist position.

For investors, this identifies a large financial institution as a key shareholder but does not, by itself, signal strategic change. Future ownership updates in subsequent beneficial ownership filings may clarify whether the stake remains stable, increases, or declines over time.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

M3-Brigade Acquisition V Corp.

(Name of Issuer)

Common Shares

(Title of Class of Securities)

G63212107

(CUSIP Number)

12/31/2025

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

SCHEDULE 13G

CUSIP No. G63212107

1

Names of Reporting Persons

Mizuho Financial Group, Inc.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

JAPAN

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 2,543,600.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 2,543,600.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,543,600.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

8.8 %

12

Type of Reporting Person (See Instructions)

FI

Comment for Type of Reporting Person: Mizuho Financial Group, Inc., Mizuho Bank, Ltd. and Mizuho Americas LLC may be deemed to be indirect beneficial owners of said equity securities directly held by Mizuho Securities USA LLC which is their wholly-owned subsidiary.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: M3-Brigade Acquisition V Corp.
(b)	Address of issuer's principal executive offices: 1700 Broadway, 19th Floor, New York, NY 10019
Item 2.
(a)	Name of person filing: Mizuho Financial Group, Inc.
(b)	Address or principal business office or, if none, residence: 1-5-5, Otemachi, Chiyoda-ku, Tokyo, 100-8176, Japan
(c)	Citizenship: Japan
(d)	Title of class of securities: Common Shares
(e)	CUSIP No.: G63212107
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
	Parent Holding Company
Item 4.	Ownership
(a)	Amount beneficially owned: 2,543,600
(b)	Percent of class: 8.8 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 2,543,600
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 2,543,600
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary. See Exhibit A
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. By signing below I certify that, to the best of my knowledge and belief, the foreign regulatory scheme applicable to Parent Holding Company is substantially comparable to the regulatory scheme applicable to the functionally equivalent U.S. institution(s). I also undertake to furnish to the Commission staff, upon request, information that would otherwise be disclosed in a Schedule 13D.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Mizuho Financial Group, Inc.

Signature:	/s/ Takahiro Katsura
Name/Title:	Takahiro Katsura, Managing Director, Global Corporate Function Coordination Department
Date:	02/12/2026

FAQ

What percentage of M3-Brigade Acquisition V Corp. (MBAV) does Mizuho Financial Group own?

Mizuho Financial Group reports beneficial ownership of 8.8% of M3-Brigade Acquisition V Corp.’s common shares. This corresponds to 2,543,600 shares, giving Mizuho a sizable but minority position in the company’s equity base as disclosed in the Schedule 13G filing.

How many M3-Brigade Acquisition V Corp. (MBAV) shares does Mizuho control?

Mizuho Financial Group reports beneficial ownership and sole voting and dispositive power over 2,543,600 common shares of M3-Brigade Acquisition V Corp. The filing shows no shared voting or dispositive power, indicating centralized control of this position within the Mizuho group.

Is Mizuho’s stake in MBAV an activist or passive investment?

Mizuho characterizes its MBAV stake as passive. It certifies the securities were acquired and are held in the ordinary course of business and not for the purpose of changing or influencing control, consistent with a Schedule 13G rather than an activist Schedule 13D filing.

Which Mizuho entity directly holds the MBAV shares reported on this Schedule 13G?

The Schedule 13G states the equity securities are directly held by Mizuho Securities USA LLC, a wholly owned subsidiary. Mizuho Financial Group, Inc., Mizuho Bank, Ltd. and Mizuho Americas LLC may be deemed indirect beneficial owners of the 2,543,600 MBAV common shares.

What is the event date for Mizuho’s 8.8% ownership disclosure in MBAV?

The Schedule 13G lists December 31, 2025 as the Date of Event requiring the filing. This date anchors when Mizuho’s beneficial ownership in M3-Brigade Acquisition V Corp. reached the disclosed level of 2,543,600 shares, representing 8.8% of the outstanding class.

Under which SEC rule is Mizuho’s MBAV Schedule 13G filed?

The filing references Rule 13d-1(b), which applies to certain institutional investors filing Schedule 13G. Mizuho identifies itself as a parent holding company, using the institutional investor framework to report its 8.8% passive ownership stake in M3-Brigade Acquisition V Corp.