Earnings Per Share

6 Months Ended

Jun. 30, 2019

Basic net income per share attributable to Vertex common shareholders is based upon the weighted-average number of common shares outstanding during the period, excluding restricted stock, restricted stock units and performance-based restricted stock units, or “PSUs,” that have been issued but are not yet vested. Diluted net income per share attributable to Vertex common shareholders is based upon the weighted-average number of common shares outstanding during the period plus additional weighted-average common equivalent shares outstanding during the period when the effect is dilutive.

The following table sets forth the computation of basic and diluted net income per share for the periods ended:



	Three Months Ended June 30,					Six Months Ended June 30,
	2019		2018			2019		2018
	(in thousands, except per share amounts)
Basic net income attributable to Vertex per common share calculation:
Net income attributable to Vertex common shareholders	$	267,427	$	207,360		$	536,058	$	417,623
Less: Undistributed earnings allocated to participating securities	—		(65		)	—		(163		)
Net income attributable to Vertex common shareholders—basic	$	267,427	$	207,295		$	536,058	$	417,460

Basic weighted-average common shares outstanding	256,154		254,135			255,941		253,685
Basic net income attributable to Vertex per common share	$	1.04	$	0.82		$	2.09	$	1.65

Diluted net income attributable to Vertex per common share calculation:
Net income attributable to Vertex common shareholders	$	267,427	$	207,360		$	536,058	$	417,623
Less: Undistributed earnings allocated to participating securities	—		(64		)	—		(160		)
Net income attributable to Vertex common shareholders—diluted	$	267,427	$	207,296		$	536,058	$	417,463

Weighted-average shares used to compute basic net income per common share	256,154		254,135			255,941		253,685
Effect of potentially dilutive securities:
Stock options	2,225		2,758			2,405		3,003
Restricted stock and restricted stock units (including PSUs)	1,440		1,689			1,655		1,851
Employee stock purchase program	3		2			14		18
Weighted-average shares used to compute diluted net income per common share	259,822		258,584			260,015		258,557
Diluted net income attributable to Vertex per common share	$	1.03	$	0.80		$	2.06	$	1.61

The Company did not include the securities in the following table in the computation of the net income per share attributable to Vertex common shareholders calculations because the effect would have been anti-dilutive during each period:



	Three Months Ended June 30,		Six Months Ended June 30,
	2019	2018	2019	2018
	(in thousands)
Stock options	3,207	2,253	3,022	1,943
Unvested restricted stock and restricted stock units (including PSUs)	3	6	4	5