Stockholders' Equity

Common Stock. In September 2001, EOG's Board of Directors (Board) authorized the purchase of an aggregate maximum of 10 million shares of Common Stock that superseded all previous authorizations. At December 31, 2017, 6,386,200 shares remained available for purchase under this authorization. EOG last purchased shares of its Common Stock under this authorization in March 2003. In addition, shares of Common Stock are from time to time withheld by, or returned to, EOG in satisfaction of tax withholding obligations arising upon the exercise of employee stock options or stock-settled stock appreciation rights (SARs), the vesting of restricted stock, restricted stock unit, performance stock or performance unit grants or in payment of the exercise price of employee stock options. Such shares withheld or returned do not count against the Board authorization discussed above. Shares purchased, withheld and returned are held in treasury for, among other purposes, fulfilling any obligations arising under EOG's stock-based compensation plans and any other approved transactions or activities for which such shares of Common Stock may be required.

On February 15, 2017, the Board approved an amendment to EOG's Restated Certificate of Incorporation to increase the number of EOG's authorized shares of common stock from 640 million to 1,280 million. EOG's stockholders approved the increase at the Annual Meeting of Stockholders on April 27, 2017, and the amendment was filed with the Delaware Secretary of State on April 28, 2017.

On October 4, 2016, EOG issued approximately 25 million shares of EOG common stock in connection with the Yates transaction. See Note 17.

EOG declared and paid quarterly cash dividends of $0.1675 per share in 2017, 2016 and 2015. On February 27, 2018, EOG's Board increased the quarterly cash dividend on the common stock by 10% from the current $0.1675 per share to $0.1850 per share, effective beginning with the dividend to be paid on April 30, 2018, to stockholders of record as of April 16, 2018.

The following summarizes Common Stock activity for each of the years ended December 31, 2015, 2016 and 2017 (in thousands):



	Common Shares
	Issued	Treasury		Outstanding

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
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


(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.

Preferred Stock. EOG currently has one authorized series of preferred stock. As of December 31, 2017, there were no shares of preferred stock outstanding.