Earnings Per Common Share

The following is a reconciliation of the numerators and denominators of the basic and diluted earnings per common share computations for the six months and three months ended June 30, 2016 and 2015 (in millions, except per share amounts):



	Six Months Ended June 30,				Three Months Ended June 30,
	2016		2015		2016		2015
Basic:
Net income attributable to Intercontinental Exchange, Inc.	$	726	$	598	$	357	$	283
Weighted average common shares outstanding	119		112		119		111
Basic earnings per common share	$	6.10	$	5.37	$	3.00	$	2.55
Diluted:
Weighted average common shares outstanding	119		112		119		111
Effect of dilutive securities - stock options and restricted shares	1		—		1		1
Diluted weighted average common shares outstanding	120		112		120		112
Diluted earnings per common share	$	6.07	$	5.34	$	2.98	$	2.54

Basic earnings per common share is calculated using the weighted average common shares outstanding during the period. The weighted average common shares outstanding increased for the six months and three months ended June 30, 2016, over the prior year period, primarily due to stock issued for the Interactive Data and Trayport acquisitions in December 2015, partially offset by stock repurchases during 2015. We issued 6.5 million shares of our common stock to Interactive Data stockholders and 2.5 million shares of our common stock to Trayport stockholders, weighted to show these additional shares outstanding for periods after the respective acquisition dates (Note 3).

Common equivalent shares from stock options and restricted stock awards, using the treasury stock method, are included in the diluted per share calculations unless the effect of their inclusion would be antidilutive. During the six months ended June 30, 2016 and 2015, 150,323 and 190,000 outstanding stock options, respectively, were not included in the computation of diluted earnings per common share since the inclusion would have had an antidilutive effect because the outstanding stock option exercise prices were greater than the average market price of the common shares during the relevant periods. Certain figures in the table above may not recalculate due to rounding.