Mizuho Reports Sole Voting Control of 750,000 BKHAU Shares (8.4%)

Rhea-AI Filing Summary

Mizuho Financial Group reports beneficial ownership of 750,000 common shares of Black Hawk Acquisition Corporation, representing 8.4% of the outstanding class. The filing states Mizuho has sole voting and sole dispositive power over these shares, meaning it controls voting decisions and disposition of the stake. The document identifies Mizuho as a parent holding company and notes that Mizuho Bank, Mizuho Americas LLC and Mizuho Securities USA LLC may be deemed indirect beneficial owners of the shares held by Mizuho Securities USA LLC. The filing also confirms the securities were acquired and are held in the ordinary course of business and not for the purpose of changing control.

Positive

• 750,000 shares disclosed, representing a material 8.4% stake in Black Hawk Acquisition Corporation
• Sole voting and sole dispositive power clearly reported, indicating Mizuho controls voting and disposition of the shares
• Parent/subsidiary relationships (Mizuho Bank, Mizuho Americas LLC, Mizuho Securities USA LLC) are disclosed, improving transparency

Negative

• None.

Insights

Financial Analyst

TL;DR: Mizuho discloses an 8.4% stake (750,000 shares) in Black Hawk with sole voting and dispositive power; this is a material >5% disclosure.

The Schedule 13G/A is a routine but material disclosure because holdings above 5% trigger investor notice requirements. Reporting sole voting and dispositive power clarifies that Mizuho can vote and sell these shares without shared authority, which matters for shareholder votes and potential block trades. The parent/subsidiary disclosure identifies the chain of possible indirect ownership, improving transparency about who ultimately holds the economic interest.

Corporate Governance Expert

TL;DR: This filing increases transparency on ownership and control; it is informational rather than an explicit governance change.

Mizuho's declaration of sole voting power is significant for governance disclosure: it signals who can influence corporate votes. The statement that the position was acquired in the ordinary course of business and not to change control reduces immediate governance concern, but the 8.4% stake remains material for investor attention in future vote contexts. The parent holding company note appropriately maps subsidiary relationships for regulatory clarity.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 3)

Black Hawk Acquisition Corporation

(Name of Issuer)

Common Shares

(Title of Class of Securities)

G1148A101

(CUSIP Number)

06/30/2025

(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. G1148A101

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 750,000.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 750,000.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

750,000.00

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)

8.4 %

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: Black Hawk Acquisition Corporation
(b)	Address of issuer's principal executive offices: 4125 BLACKHAWK PLAZA CIRCLE SUITE 166 DANVILLE, CA, 94506
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.: G1148A101
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: 750,000
(b)	Percent of class: 8.4 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 750,000
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 750,000
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
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:	08/13/2025

FAQ

What stake does Mizuho Financial Group hold in Black Hawk Acquisition Corporation (BKHAU)?

Mizuho Financial Group reports beneficial ownership of 750,000 shares, representing 8.4% of the class.

Does Mizuho have voting or disposition control over its BKHAU shares?

Yes. The filing reports sole voting power and sole dispositive power over the 750,000 shares.

Is the Mizuho position held directly or through subsidiaries?

The filing states Mizuho is a parent holding company and notes that Mizuho Bank, Mizuho Americas LLC and Mizuho Securities USA LLC may be deemed indirect beneficial owners of the shares held by Mizuho Securities USA LLC.

Was the stake acquired to change control of Black Hawk?

The filing certifies the securities were acquired and are held in the ordinary course of business and not to change or influence control of the issuer.

What type of SEC filing reports this ownership disclosure?

This disclosure is made on a Schedule 13G/A, a form used to report beneficial ownership above certain thresholds under the Exchange Act.