The following summarizes Common Stock activity for each of the years ended December 31, 2016, 2017 and 2018 (in thousands):



	Common Shares
	Issued	Treasury		Outstanding

Balance at December 31, 2015	550,151	(292	)	549,859
Common Stock Issued	25,204	—		25,204
Common Stock Issued Under Stock-Based Compensation Plans	1,500	—		1,500
Treasury Stock Purchased ⁽¹⁾	—	(922	)	(922	)
Common Stock Issued Under Employee Stock Purchase Plan	95	117		212
Treasury Stock Issued Under Stock-Based Compensation Plans	—	847		847
Balance at December 31, 2016	576,950	(250	)	576,700
Common Stock Issued Under Stock-Based Compensation Plans	1,878	—		1,878
Treasury Stock Purchased ⁽¹⁾	—	(686	)	(686	)
Common Stock Issued Under Employee Stock Purchase Plan	—	180		180
Treasury Stock Issued Under Stock-Based Compensation Plans	—	405		405
Balance at December 31, 2017	578,828	(351	)	578,477
Common Stock Issued Under Stock-Based Compensation Plans	1,580	—		1,580
Treasury Stock Purchased ⁽¹⁾	—	(539	)	(539	)
Common Stock Issued Under Employee Stock Purchase Plan	—	180		180
Treasury Stock Issued Under Stock-Based Compensation Plans	—	325		325
Balance at December 31, 2018	580,408	(385	)	580,023


(1)	Represents shares that were withheld by or returned to EOG (i) in satisfaction of tax withholding obligations that arose upon the exercise of employee stock options or SARs or the vesting of restricted stock, restricted stock unit, performance stock or performance unit grants or (ii) in payment of the exercise price of employee stock options.