Earnings Per Share

12 Months Ended

Dec. 31, 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:



	2019		2018			2017
	(in thousands, except per share amounts)
Basic net income attributable to Vertex per common share calculation:
Net income attributable to Vertex common shareholders	$	1,176,810	$	2,096,896		$	263,484
Less: Undistributed earnings allocated to participating securities	—		(501		)	(293		)
Net income attributable to Vertex common shareholders—basic	$	1,176,810	$	2,096,395		$	263,191

Basic weighted-average common shares outstanding	256,728		254,292			248,858
Basic net income attributable to Vertex per common share	$	4.58	$	8.24		$	1.06

Diluted net income attributable to Vertex per common share calculation:
Net income attributable to Vertex common shareholders	$	1,176,810	$	2,096,896		$	263,484
Less: Undistributed earnings allocated to participating securities	—		(492		)	(288		)
Net income attributable to Vertex common shareholders—diluted	$	1,176,810	$	2,096,404		$	263,196

Weighted-average shares used to compute basic net income per common share	256,728		254,292			248,858
Effect of potentially dilutive securities:
Stock options	2,231		2,913			2,797
Restricted stock and restricted stock units (including PSUs)	1,700		1,963			1,542
Employee stock purchase program	14		17			28
Weighted-average shares used to compute diluted net income per common share	260,673		259,185			253,225
Diluted net income attributable to Vertex per common share	$	4.51	$	8.09		$	1.04

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.



	2019	2018	2017
	(in thousands)
Stock options	2,833	2,217	3,554
Unvested restricted stock and restricted stock units (including PSUs)	6	5	411