Calculation of Earnings per Share

3 Months Ended

Mar. 31, 2016

Basic earnings per share is calculated by dividing net income by the weighted-average number of shares outstanding during the period. Diluted earnings per share is calculated by dividing net income attributable to VCA Inc. by the weighted-average number of common shares outstanding, after giving effect to all dilutive potential common shares outstanding during the period. Basic and diluted earnings per share were calculated as follows (in thousands, except per share amounts):



	Three Months Ended March 31,
	2016		2015
Net income attributable to VCA Inc.	$	46,227	$	38,301
Weighted-average common shares outstanding:
Basic	80,776		82,347
Effect of dilutive potential common shares:
Stock options	284		340
Non-vested shares and units	463		686
Diluted	81,523		83,373
Basic earnings per common share	$	0.57	$	0.47
Diluted earnings per common share	$	0.57	$	0.46

For the three months ended March 31, 2016 and 2015, potential common shares of 40,193 and 77,186, respectively, were excluded from the computation of diluted earnings per share because their inclusion would have had an antidilutive effect.