Deferred compensation awards (Tables)

12 Months Ended

Mar. 31, 2020

Deferred Compensation Awards [Abstract]

Activity relating to RSU awards

	Outstanding (number of Nomura shares)			Weighted-average grant date fair value per share		Weighted-average remaining life until expiry (years)
Outstanding as of March 31, 2019		48,518,200		¥	530		1.3
Granted		33,786,200			365
Forfeited		(3,734,800	)		441
Delivered		(15,230,000	)		530
Outstanding as of March 31, 2020		63,339,600		¥	447		1.0

SAR Plan A awards, Weighted-average assumptions

	Year ended March 31
	2018			2019			2020
Expected volatility		35.30	%		33.30	%		—	%
Expected dividends yield		3.07	%		3.67	%		—	%
Expected lives (in years)		4.5			4.5			—
Risk-free interest rate		0.10	%		0.10	%		—	%

Activity relating to SAR Plan A awards

	Outstanding (number of Nomura shares)			Weighted-average exercise price		Weighted-average remaining life until expiry (years)
Outstanding as of March 31, 2019		16,539,300		¥	679		3.9
Granted		—			—
Exercised		(900,800	)		298
Forfeited		(89,900	)		630
Expired		(95,700	)		298
Outstanding as of March 31, 2020		15,452,900		¥	704		3.1
Exercisable as of March 31, 2020		12,945,000		¥	729		2.6

Activity relating to SAR Plan B awards

	Outstanding (number of Nomura shares)			Weighted-average grant date fair value per share		Weighted-average remaining life until expiry (years)
Outstanding as of March 31, 2019		39,392,900		¥	508		4.1
Granted		—			—
Exercised		(16,340,900	)		497
Forfeited		(399,900	)		531
Expired		(313,200	)		425
Outstanding as of March 31, 2020		22,338,900		¥	517		3.4
Exercisable as of March 31, 2020		16,186,800		¥	512		2.5

Activity related to NSU and CSU awards

	NSUs						CSUs
	Outstanding (number of units)			Stock price			Outstanding (number of units)			Stock price
Outstanding as of March 31, 2019		31,036,558		¥	389			8,760,439		¥	603
Granted		13,203,853			405	(1)		—			—
Vested		(22,762,553	)		438	(2)		(5,728,731	)		601	(2)
Forfeited		(379,029	)					(230,052	)
Outstanding as of March 31, 2020		21,098,829		¥	445	(3)		2,801,656		¥	611	(3)

(1) Weighted-average price of the Company’s common stock used to determine number of awards granted.

(2) Weighted-average price of the Company’s common stock used to determine the final cash settlement amount of the awards.

(3) The price of the Company’s common stock used to remeasure the fair value of the remaining outstanding unvested awards as of March 31, 2020.

Activity relating to NIU awards

	Outstanding (number of units)			Index price(1)
Outstanding as of March 31, 2019		5,165,744		$	6,043
Granted		—			—
Vested		(4,127,154	)		6,233	(2)
Forfeited		(198,636	)
Outstanding as of March 31, 2020		839,954		$	5,339	(3)

(1) The price of each unit is determined using 1/1000th of the index price.

(2) Weighted-average index price used to determine the final cash settlement amount of the awards.

(3) Index price used to remeasure the total fair value of the remaining outstanding unvested awards as of March 31, 2020.