A summary of stock option and SAR activity for the three months ended March 31, 2026 is as follows (in millions, except share amounts which are reflected in thousands, per share amounts, and years):


	SARs Outstanding Number of SARs	Options Outstanding Number of Shares	Weighted-Average Exercise Price Per Share		Weighted-Average Remaining Contractual Life (in years)	Aggregate Intrinsic Value
As of December 31, 2025	16	5,868	$	48.72	4.79	$	194
Granted	—	517	$	75.95
Exercised	(3)	(61)	$	19.79
Canceled and forfeited	—	(73)	$	59.51
As of March 31, 2026	13	6,251	$	51.14	4.77	$	136
Exercisable as of March 31, 2026	13	2,445	$	31.23	3.17	$	101

The following table summarizes the activity related to our RSUs for the three months ended March 31, 2026 (in thousands, except per share amounts):


	Number of Shares	Weighted-Average Grant-Date Fair Value per Share
Unvested and outstanding as of December 31, 2025	57,654	$	65.69
Granted	32,057	$	73.44
Vested	(8,936)	$	51.89
Canceled and forfeited	(2,198)	$	67.60
Unvested and outstanding as of March 31, 2026	78,577	$	70.36

Stock-based compensation expense is allocated based on the cost center to which the award holder belongs. The following table summarizes total stock-based compensation expense by function (in millions):


	Three Months Ended March 31,
	2025		2026
Operations and support	$	52	$	60
Sales and marketing	24		25
Research and development	264		286
General and administrative	95		102
Total	$	435	$	473

As of March 31, 2026, there was $5.3 billion of unamortized compensation costs related to all unvested awards. The unamortized compensation costs are expected to be recognized over a weighted-average period of approximately 3.09 years.

The income tax benefits recognized in the condensed consolidated statements of operations for stock-based compensation expense were not material during the three months ended March 31, 2025 and 2026.

In July 2025, our board of directors authorized an additional $20.0 billion for the repurchase of common stock (“Share Repurchase Program”). The timing, manner, price and amount of any repurchases are determined by the discretion of management, depending on market conditions and other factors. Repurchases may be made through open market purchases and accelerated share repurchases. The exact number of shares to be repurchased by us, if any, is not guaranteed. Depending on market conditions and other factors, these repurchases may be commenced or suspended at any time or periodically without prior notice.

During the three months ended March 31, 2025 and 2026, we repurchased, and subsequently retired, 26.6 million and 39.7 million shares of common stock for $1.8 billion and $3.0 billion, respectively, excluding broker commissions and fees. As of March 31, 2026, we had approximately $16.2 billion available to repurchase shares pursuant to the Share Repurchase Program.

The Inflation Reduction Act imposed a nondeductible 1% excise tax on the net value of certain stock repurchases. During the three months ended March 31, 2025 and 2026, the excise tax on net share repurchases was not material.