The following summarizes Common Stock activity for each of the years ended December 31, 2013, 2014 and 2015 (in thousands):



	Common Shares
	Issued	Treasury		Outstanding

Balance at December 31, 2012	543,916	(652	)	543,264
Common Stock Issued Under Stock-Based Compensation Plans	2,206	—		2,206
Treasury Stock Purchased ⁽¹⁾	—	(854	)	(854	)
Common Stock Issued Under Employee Stock Purchase Plan	256	—		256
Treasury Stock Issued Under Stock-Based Compensation Plans	—	1,300		1,300
Balance at December 31, 2013	546,378	(206	)	546,172
Common Stock Issued Under Stock-Based Compensation Plans	2,448	—		2,448
Treasury Stock Purchased ⁽¹⁾	—	(1,209	)	(1,209	)
Common Stock Issued Under Employee Stock Purchase Plan	202	—		202
Treasury Stock Issued Under Stock-Based Compensation Plans	—	682		682
Balance at December 31, 2014	549,028	(733	)	548,295
Common Stock Issued Under Stock-Based Compensation Plans	1,019	—		1,019
Treasury Stock Purchased ⁽¹⁾	—	(581	)	(581	)
Common Stock Issued Under Employee Stock Purchase Plan	104	121		225
Treasury Stock Issued Under Stock-Based Compensation Plans	—	901		901
Balance at December 31, 2015	550,151	(292	)	549,859


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