Net Income per Share

6 Months Ended

Jun. 30, 2015

Basic net income per common share is computed by dividing net income applicable to common shares by the weighted average number of common shares outstanding during the period. Diluted net income per common share is determined based on the assumption that dilutive restricted stock and restricted stock unit awards have vested and outstanding dilutive stock options have been exercised and the aggregate proceeds were used to reacquire common stock using the average price of such common stock for the period. The total number of shares issued or reserved for future issuance under outstanding stock options at June 30, 2015 and 2014 was 9,321,649 and 9,425,725, respectively, and the total number of shares of restricted stock and shares reserved for restricted stock units outstanding at June 30, 2015 and 2014 was 1,470,813 and 1,453,366, respectively. All outstanding stock options for the three and six months ended June 30, 2015 were anti-dilutive.

The following table summarizes the computation of basic and diluted net income per common share (in thousands, except per share amounts):



	Three Months Ended June 30,				Six Months Ended June 30,
	2015		2014		2015		2014
Net income attributable to ION	$	56,069	$	1,188	$	805	$	77,167
Weighted average number of common shares outstanding	164,693		164,063		164,630		163,956
Effect of dilutive stock awards	19		360		21		287
Weighted average number of diluted common shares outstanding	164,712		164,423		164,651		164,243
Basic net income per share	$	0.34	$	0.01	$	0.00	$	0.47
Diluted net income per share	$	0.34	$	0.01	$	0.00	$	0.47