Regulatory matters

12 Months Ended

Mar. 31, 2026

17. Regulatory matters

Regulatory capital requirements

MHFG, MHBK, and MHTB are subject to regulatory capital requirements supervised by the Financial Services Agency in accordance with the provisions of Japan’s Banking Act and related regulations. Certain foreign banking subsidiaries are subject to regulation and control by local supervisory authorities, including central banks. Failure to meet minimum capital requirements may initiate certain mandatory actions by regulators that, if undertaken, could have a direct material effect on the MHFG Group’s consolidated financial condition and results of operations.

The capital requirements and regulatory adjustments are being phased in over a transitional period as follows:


	March 2025			March 2026			March 2027			March 2028
Minimum Common Equity Tier 1 capital		4.5	%		4.5	%		4.5	%		4.5	%
Minimum Tier 1 capital		6.0	%		6.0	%		6.0	%		6.0	%
Minimum total capital		8.0	%		8.0	%		8.0	%		8.0	%
Capital conservation buffer		2.5	%		2.5	%		2.5	%		2.5	%
Countercyclical capital buffer (1)		0.11	%		0.13	%		0.13	%		0.13	%
Additional loss absorbency requirements for G-SIBs and D-SIBs (2)		1.0	%		1.0	%		1.0	%		1.0	%
Minimum Leverage Ratio (3)		3.7	%		3.7	%		3.7	%		3.7	%

Notes:

(1)	Figures assume that the countercyclical capital buffer will continue to be 0.13% after March 2026.

(2)	Figures assume that the additional loss absorbency requirements applied to the Group as a G-SIB and D-SIB continue to be 1.0% on a fully effective basis in future years.

(3)	The ratios disclosed above include a leverage ratio buffer required to be met at 50% of the additional loss absorbency requirements applied to the Group as a G-SIB under the finalized Basel III reforms.

If the capital adequacy ratio and leverage ratio of a financial institution falls below the required level, the Financial Services Agency may, depending upon the extent of capital deterioration, take certain corrective action, including requiring the financial institution to submit an improvement plan to strengthen its capital base, reduce its total assets, restrict its business operations or other actions that could have a material effect on its financial condition and results of operations.

Capital adequacy ratios and leverage ratios of MHFG, MHBK, and MHTB as of March 31, 2025 and 2026 calculated in accordance with Japanese GAAP and the guidelines established by the Financial Services Agency are set forth in the following table:


	2025				2026
	Amount		Ratio		Amount		Ratio
	(in billions of yen, except percentages)
Consolidated:
MHFG:
Common Equity Tier 1 capital:
Required (1)		5,826		8.11		6,579		8.13
Actual		9,506		13.23		10,650		13.16
Tier 1 capital:
Required (1)		6,904		9.61		7,793		9.63
Actual		11,248		15.65		12,733		15.73
Total risk-based capital:
Required (1)		8,341		11.61		9,411		11.63
Actual		12,755		17.75		14,252		17.61
Leverage Ratio (2) :
Required (3)		8,715		3.70		9,658		3.70
Actual		11,248		4.77		12,733		4.87


	2025				2026
	Amount		Ratio		Amount		Ratio
	(in billions of yen, except percentages)
MHBK:
Common Equity Tier 1 capital:
Required		2,964		4.50		3,339		4.50
Actual		7,529		11.42		8,586		11.57
Tier 1 capital:
Required		3,952		6.00		4,452		6.00
Actual		9,267		14.06		10,673		14.38
Total risk-based capital:
Required		5,270		8.00		5,936		8.00
Actual		10,718		16.27		12,161		16.38
Leverage Ratio (2) :
Required		6,837		3.15		7,578		3.15
Actual		9,267		4.26		10,673		4.43
MHTB:
Common Equity Tier 1 capital:
Required		70		4.50		—		—
Actual		493		31.60		—		—
Tier 1 capital:
Required		93		6.00		—		—
Actual		493		31.60		—		—
Total risk-based capital:
Required		125		8.00		—		—
Actual		493		31.60		—		—
Leverage Ratio (2) (4) :
Required		115		3.15		—		—
Actual		493		13.49		—		—
Core capital (4) :
Required		—		—		59		4.00
Actual		—		—		436		29.28
Non-consolidated:
MHBK:
Common Equity Tier 1 capital:
Required		2,737		4.50		3,086		4.50
Actual		6,116		10.05		6,758		9.85
Tier 1 capital:
Required		3,649		6.00		4,115		6.00
Actual		7,843		12.89		8,832		12.87
Total risk-based capital:
Required		4,866		8.00		5,487		8.00
Actual		9,258		15.22		10,319		15.04
Leverage Ratio (2) :
Required		6,240		3.15		6,763		3.15
Actual		7,843		3.95		8,832		4.11
MHTB:
Common Equity Tier 1 capital:
Required		66		4.50		—		—
Actual		454		30.86		—		—


	2025				2026
	Amount		Ratio		Amount		Ratio
	(in billions of yen, except percentages)
Tier 1 capital:
Required		88		6.00		—		—
Actual		454		30.86		—		—
Total risk-based capital:
Required		117		8.00		—		—
Actual		454		30.86		—		—
Leverage Ratio (2) (4) :
Required		110		3.15		—		—
Actual		454		12.98		—		—
Core capital (4) :
Required		—		—		57		4.00
Actual		—		—		416		29.04

Notes:

(1)

The required ratios disclosed above, at March 31, 2025 and 2026, include the capital conservation buffer of 2.5%, the countercyclical capital buffer of 0.11% and 0.13%, respectively, and the additional loss absorbency requirements for

G-SIBs

and

D-SIBs

of 1.0%, which are all in addition to the regulatory minima. The respective required amounts are determined by applying the ratios to the sum of the risk weighted assets and certain other risk amounts.

(2)	The required and actual amounts disclosed above at March 31, 2025 and 2026 exclude amounts of deposits to the Bank of Japan.

(3)	The required ratios disclosed above, at March 31, 2025 and 2026, include a leverage ratio buffer required to be met at 50% of the additional loss absorbency requirements applied to the Group as a G-SIB under the finalized Basel III reforms.

(4)

The core capital ratio is a Japan-specific regulatory indicator that measures capital adequacy under the domestic standard applicable to banks with only domestic operations. Since transitioning to a domestic standard applicable to banks with only domestic operations from December 31, 2025, Mizuho Trust & Banking is subject to the domestic standard and is no longer subject to the leverage ratio requirements.

MHFG’s securities subsidiary in Japan is also subject to the capital adequacy requirement under Japan’s Financial Instruments and Exchange Act. Under this requirement, securities firms must maintain a minimum capital adequacy ratio of 120% calculated as a percentage of capital accounts less certain assets, as calculated using Japanese GAAP figures, against amounts equivalent to market, counterparty, and basic risks. Specific guidelines are issued as a ministerial ordinance that details the definition of essential components of the capital ratios, including capital, disallowed assets and risks, and related measures. Failure to maintain a minimum capital ratio will trigger mandatory regulatory actions. A capital ratio of less than 140% will call for regulatory reporting and a capital ratio of less than 100% may lead to a temporary suspension of all or part of the business operations and further, to the cancellation of the license to act as a securities broker and dealer.

Management believes, as of each latest balance sheet date, that MHFG, MHBK, MHTB, and their securities subsidiary in Japan and foreign banking subsidiaries were in compliance with all capital adequacy requirements to which they were subject.