STOCKHOLDERS' EQUITY

12 Months Ended

Dec. 31, 2020

Common Stock

The following table shows the beginning and ending balances of our issued and outstanding common stock for the year ended December 31, 2020, 2019, and 2018:


	Year Ended December 31,
	2020	2019	2018
Shares issued and outstanding, beginning balance	69,065,491	70,596,559	69,818,392
Issuance of common stock from vested restricted stock units (1)	659,689	1,036,119	1,634,271
Issuance of common stock from exercise of stock options	81,026	187,504	617,157
Issuance of common stock for employee stock purchase plan	236,887	207,324	175,966
Repurchase of common stock	(3,307,074)	(2,510,376)	(1,190,995)
Awards effectively repurchased for required employee withholding taxes	(279,356)	(451,639)	(458,232)
Shares issued and outstanding, ending balance	66,456,663	69,065,491	70,596,559

(1) Net of shares of common stock underlying cancelled RSAs

Stock Repurchases

In February 2020, our board of directors authorized a $300 million incremental increase to our ongoing stock repurchase program. This repurchase authorization has no expiration. We retire shares in the period they are acquired and account for the payment as a reduction to stockholders' equity.

The following table summarizes the share repurchases under this program for the years ended December 31, 2020, 2019 and 2018:


	Year Ended December 31,
	2020		2019		2018
Total cost (in millions)	$	178	$	140	$	61
Total shares	3,307,074		2,510,376		1,190,995
Average price per share	$	53.85	$	55.64	$	51.22

As of December 31, 2020, $358 million remains available for repurchase under all authorizations approved by the board of directors.