Earnings per Share

6 Months Ended

Jun. 30, 2016

The Company has unvested shares of restricted stock and restricted stock units outstanding that are considered participating securities and, therefore, computes basic and diluted earnings per share under the two-class method. Basic earnings per share for the periods are based upon the weighted average number of shares of common stock outstanding during the periods. Diluted earnings per share include the effect of certain stock options.



	Three Months Ended June 30,						Six Months Ended June 30,
	2016			2015			2016			2015
Net income attributable to Westlake Chemical Corporation	$	111,124		$	205,095		$	234,252		$	351,437
Less:
Net income attributable to participating securities	(504		)	(253		)	(1,054		)	(457		)
Net income attributable to common shareholders	$	110,620		$	204,842		$	233,198		$	350,980

The following table reconciles the denominator for the basic and diluted earnings per share computations shown in the consolidated statements of operations:



	Three Months Ended June 30,				Six Months Ended June 30,
	2016		2015		2016		2015
Weighted average common shares—basic	129,583,224		132,538,123		129,886,594		132,625,857
Plus incremental shares from:
Assumed exercise of options	397,303		506,852		403,927		498,840
Weighted average common shares—diluted	129,980,527		133,044,975		130,290,521		133,124,697

Earnings per common share attributable to Westlake Chemical Corporation:
Basic	$	0.85	$	1.55	$	1.80	$	2.65
Diluted	$	0.85	$	1.54	$	1.79	$	2.64

Excluded from the computation of diluted earnings per share are options to purchase 695,040 and 330,315 shares of common stock for the three months ended June 30, 2016 and 2015, respectively, and 625,494 and 285,933 shares of common stock for the six months ended June 30, 2016 and 2015, respectively. These options were outstanding during the periods reported but were excluded because the effect of including them would have been antidilutive.