The following summarizes Common Stock activity for each of the years ended December 31, 2014, 2015 and 2016 (in thousands): | | | | | | | | | | | Common Shares | | Issued | | Treasury | | Outstanding | | | | | | | 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 |
| 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 |
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| | (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. |
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