NET INCOME PER SHARE ATTRIBUTABLE TO GILEAD COMMON STOCKHOLDERS

Basic net income per share attributable to Gilead common stockholders is calculated based on the weighted-average number of shares of our common stock outstanding during the period. Diluted net income per share attributable to Gilead common stockholders is calculated based on the weighted-average number of shares of our common stock outstanding and other dilutive securities outstanding during the period. The potentially dilutive shares of our common stock resulting from the assumed exercise of outstanding stock options and equivalents were determined under the treasury stock method.

We have excluded stock options and equivalents of 21 million and 16 million for the three and six months ended June 30, 2018, respectively, and 13 million and 10 million for the three and six months ended June 30, 2017, respectively, from the computation of diluted net income per share attributable to Gilead common stockholders because their effect was antidilutive.

The following table summarizes the calculation of basic and diluted net income per share attributable to Gilead common stockholders (in millions, except per share amounts):



	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2018		2017		2018		2017
Net income attributable to Gilead	$	1,817	$	3,073	$	3,355	$	5,775
Shares used in per share calculation - basic	1,298		1,307		1,302		1,307
Dilutive effect of stock options and equivalents	10		10		12		12
Shares used in per share calculation - diluted	1,308		1,317		1,314		1,319
Net income per share attributable to Gilead common stockholders - basic	$	1.40	$	2.35	$	2.58	$	4.42
Net income per share attributable to Gilead common stockholders - diluted	$	1.39	$	2.33	$	2.55	$	4.38