Earnings and Dividends per Share

The Company has unvested 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.



	Year Ended December 31,
	2018			2017			2016
Net income attributable to Westlake Chemical Corporation	$	996		$	1,304		$	399
Less:
Net income attributable to participating securities	(5		)	(7		)	(2		)
Net income attributable to common shareholders	$	991		$	1,297		$	397

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



	Year Ended December 31,
	2018		2017		2016
Weighted average common shares—basic	129,401,823		129,087,043		129,367,712
Plus incremental shares from:
Assumed exercise of options	583,930		452,970		607,110
Weighted average common shares—diluted	129,985,753		129,540,013		129,974,822

Earnings per common share attributable to Westlake Chemical Corporation:
Basic	$	7.66	$	10.05	$	3.07
Diluted	$	7.62	$	10.00	$	3.06

Excluded from the computation of diluted earnings per share for the years ended December 31, 2018 and 2016 are options to purchase 150,479 and 318,259 shares of common stock, respectively. There are no antidilutive options to purchase shares of common stock for the year ended December 31, 2017. These options were outstanding during the periods reported but were excluded because the effect of including them would have been antidilutive.

Dividends per Share

Dividends per common share for the years ended December 31, 2018, 2017, and 2016 were as follows:



	Year Ended December 31,
	2018		2017		2016
Dividends per common share	$	0.9200	$	0.8012	$	0.7442