4. Net Income Per Common Share

Basic earnings per common share is calculated by dividing net income available to common stockholders by the weighted average number of common shares outstanding for the period. Diluted earnings per common share reflects the assumed conversion of all potentially dilutive securities, consisting of stock options and restricted stock awards, for which the estimated fair value exceeds the exercise price, less shares which could have been purchased with the related proceeds, unless anti-dilutive. For employee equity awards, repurchased shares are also included for any unearned compensation adjusted for tax.

The table below reflects the calculation of the weighted average number of common shares outstanding, on an as if converted basis, used in computing basic and diluted earnings per common share.


	Three Months Ended March 31,
	2018		2017
Denominator:
Basic weighted average shares outstanding		47,432		46,748
Effect of dilutive stock options and restricted stock		965		1,322

Diluted weighted average shares outstanding		48,397		48,070

Diluted weighted average shares outstanding excludes the incremental effect of unvested restricted stock and shares that would be issued upon the assumed exercise of stock options in accordance with the treasury stock method. For the three months ended March 31, 2018 and 2017, approximately 0 and 8, respectively, of the University’s stock options and restricted stock awards outstanding were excluded from the calculation of diluted earnings per share as their inclusion would have been anti-dilutive. These options and restricted stock awards could be dilutive in the future.