Our stock-based compensation expense is associated with restricted stock units, or RSUs, performance stock units that are based on our corporate financial performance targets, or PSUs, performance stock units that are based on market conditions, or market-based PSUs, and our employee stock purchase plan, or ESPP.

Our Condensed Consolidated Statements of Income include stock-based compensation expense, net of amounts allocated to inventory, as follows:


	Three Months Ended				Six Months Ended
	July 31, 2022		August 1, 2021		July 31, 2022		August 1, 2021

	(In millions)
Cost of revenue	$	38	$	32	$	76	$	57
Research and development	452		297		836		573
Sales, general and administrative	159		136		315		264
Total	$	649	$	465	$	1,227	$	894

The following is a summary of our equity award transactions under our equity incentive plans:


	RSUs, PSUs, and Market-based PSUs Outstanding
	Number of Shares	Weighted Average Grant-Date Fair Value Per Share

	(In millions, except per share data)
Balances, January 30, 2022	46	$	114.19
Granted	22	$	187.51

Vested restricted stock	(11)	$	86.77
Canceled and forfeited	(1)	$	131.19
Balances, July 31, 2022	56	$	148.43

As of July 31, 2022, there was $7.61 billion of aggregate unearned stock-based compensation expense. This amount is expected to be recognized over a weighted average period of 2.8 years for RSUs, PSUs, and market-based PSUs, and 1.0 year for ESPP.