13. Earnings Per Share

Basic earnings per share (EPS) was computed by dividing net income attributable to common stock, net of income allocated to participating securities, by the weighted-average number of common shares outstanding during each period, net of treasury shares and including vested but unissued shares and share units. The computation of diluted EPS reflects the additional dilutive effect of stock options and unvested stock awards. Occidental’s instruments containing rights to nonforfeitable dividends granted in stock-based awards are considered participating securities prior to vesting and, therefore, net income allocated to these participating securities has been deducted from earnings in computing basic and diluted EPS under the two-class method. The following table presents the calculation of basic and diluted EPS for the three months ended March 31, 2018, and 2017 (in millions, except per-share amounts):


	Three months ended March 31
	2018		2017

Basic EPS
Net Income	$	708	$	117
Less: Net income allocated to participating securities		(3)		—
Net Income, net of participating securities		705		117

Weighted average number of basic shares		765.6		764.4
Basic EPS	$	0.92	$	0.15
Diluted EPS
Net income, net of participating securities	$	705	$	117
Weighted average number of basic shares		765.6		764.4
Dilutive effect of potentially dilutive securities		1.4		0.8
Total diluted weighted average common shares		767.0		765.2
Diluted EPS	$	0.92	$	0.15