Form 6-K

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 August 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 ☐

THIS REPORT ON 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NO. 333-282497) AND TO BE A PART OF SUCH PROSPECTUS FROM THE DATE ON WHICH THIS REPORT IS FURNISHED, TO THE EXTENT NOT SUPERSEDED BY DOCUMENTS OR REPORTS SUBSEQUENTLY FILED OR FURNISHED.

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:		August 14, 2026

Mizuho Financial Group, Inc.

By:		/s/ Makoto Samejima
Name:		Makoto Samejima
Title:		Senior Managing Corporate Executive / Group CFO

LOGO

August 14, 2026

To whom it may concern:


Company Name:		Mizuho Financial Group, Inc.
Representative:		Masahiro Kihara, President & CEO
Head Office:		1-5-5 Otemachi, Chiyoda-ku, Tokyo
Stock Code Number:		8411
		(Tokyo Stock Exchange (Prime Market))

Announcement regarding Capital Ratio as of June 30, 2026

Mizuho Financial Group, Inc. hereby announces Capital Ratio as of June 30, 2026, as shown in the appendix.

Capital Ratio

Consolidated

(%, Billions of yen)

Mizuho Financial Group

International Standard

As of
June 30,
2026

Change

As of
March 31,
2026

(1) Total Capital Ratio

17.74

0.13

17.61

(2) Tier 1 Capital Ratio

15.94

0.21

15.73

(3) Common Equity Tier 1 Capital Ratio

13.51

0.35

13.16

(4) Total Capital

14,590.7

337.9

14,252.8

(5) Tier 1 Capital

13,107.9

374.3

12,733.5

(6) Common Equity Tier 1 Capital

11,110.0

459.5

10,650.5

(7) Risk-weighted Assets

82,213.7

1,288.4

80,925.3

(8) Total Required Capital (7)x8%

6,577.1

103.0

6,474.0

Consolidated

Non-Consolidated

Mizuho Bank

International Standard

As of
June 30,
2026

Change

As of
March 31,
2026

As of
June 30,
2026

(1) Total Capital Ratio

16.56

0.18

16.38

15.39

(2) Tier 1 Capital Ratio

14.59

0.21

14.38

13.28

(3) Common Equity Tier 1 Capital Ratio

11.95

0.38

11.57

10.45

(4) Total Capital

12,546.0

384.1

12,161.9

10,818.4

(5) Tier 1 Capital

11,054.9

381.8

10,673.0

9,333.8

(6) Common Equity Tier 1 Capital

9,055.8

469.0

8,586.8

7,347.0

(7) Risk-weighted Assets

75,754.9

1,549.3

74,205.5

70,274.2

(8) Total Required Capital (7)x8%

6,060.3

123.9

5,936.4

5,621.9

Consolidated

Non-Consolidated

Mizuho Trust & Banking

Domestic Standard

As of
June 30,
2026

Change

As of
March 31,
2026

As of
June 30,
2026

(1) Capital Ratio

31.05

1.77

29.28

30.78

(2) Core Capital

444.7

8.3

436.4

424.8

(3) Risk-weighted Assets

1,432.0

(58.0

)

1,490.0

1,380.0

(4) Total Required Capital (3)x4%

57.2

(2.3

)

59.6

55.2

Consolidated

Non-Consolidated

Mizuho Trust & Banking

International Standard (Reference)

As of
June 30,
2026

Change

As of
March 31,
2026

As of
June 30,
2026

(1) Total Capital Ratio

33.98

1.66

32.32

33.81

(2) Tier 1 Capital Ratio

33.92

1.67

32.25

33.75

(3) Common Equity Tier 1 Capital Ratio

33.92

1.68

32.24

33.75