Regulatory matters (Tables)

12 Months Ended

Mar. 31, 2026

Capital Requirements and Regulatory Adjustments Over Transitional Period

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.

Capital Adequacy Ratios of MHFG, MHBK, and MHTB Calculated in Accordance with Japanese GAAP and Guidelines Established by Financial Services Agency

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.