Earnings Per Share

Basic earnings per share is computed using the weighted-average number of outstanding shares of common stock during the period. Diluted earnings per share is computed using the weighted-average number of outstanding shares of common stock and, when dilutive, potential common shares outstanding during the period. Potential common shares consist of incremental shares issuable upon the assumed exercise of stock options. The computation of earnings per share is as follows:



	Three Months Ended				Nine Months Ended
	September 30, 2018		September 30, 2017		September 30, 2018		September 30, 2017
	(in thousands, except per share data)
Basic earnings per share:
Net income	$	402,835	$	129,590	$	1,077,308	$	373,412
Shares used in computation:
Weighted-average common shares outstanding	435,809		432,404		435,033		431,473
Basic earnings per share	$	0.92	$	0.30	$	2.48	$	0.87

Diluted earnings per share:
Net income	$	402,835	$	129,590	$	1,077,308	$	373,412
Shares used in computation:
Weighted-average common shares outstanding	435,809		432,404		435,033		431,473
Employee stock options	16,110		14,958		16,250		14,894
Weighted-average number of shares	451,919		447,362		451,283		446,367
Diluted earnings per share	$	0.89	$	0.29	$	2.39	$	0.84

Employee stock options with exercise prices greater than the average market price of the common stock were excluded from the diluted calculation as their inclusion would have been anti-dilutive. These anti-dilutive stock options were immaterial for each period presented.