Earnings Per Share and Equity (Exelon)

12 Months Ended

Dec. 31, 2015

(Exelon)

Diluted earnings per share is calculated by dividing Net income attributable to common shareholders by the weighted average number of shares of common stock outstanding, including shares to be issued upon exercise of stock options, performance share awards and restricted stock outstanding under Exelon’s LTIPs considered to be common stock equivalents. The following table sets forth the components of basic and diluted earnings per share and shows the effect of the stock options, performance share awards and restricted stock on the weighted average number of shares outstanding used in calculating diluted earnings per share:



	Year Ended December 31,
	2015		2014		2013
Net income attributable to common shareholders	$	2,269	$	1,623	$	1,719
Weighted average common shares outstanding—basic	890		860		856
Assumed exercise and/or distributions of stock-based awards	3		4		4
Weighted average common shares outstanding—diluted	893		864		860

The number of stock options not included in the calculation of diluted common shares outstanding due to their antidilutive effect was approximately 16 million in 2015, 17 million in 2014, and 20 million in 2013. The number of equity units related to the PHI merger not included in the calculation of diluted common shares outstanding due to their antidilutive effect was 3 million for the year ended December 2015 and less than 1 million for the year ended December 31, 2014. Additionally, there were no forward units related to the PHI merger not included in the calculation of diluted common shares outstanding due to their antidilutive effect for the years ended December 31, 2015 and 2014. Refer to Note 19 — Shareholder's Equity for further information regarding the equity units and equity forward units.

Under share repurchase programs, 35 million shares of common stock are held as treasury stock with a cost of $2.3 billion as of December 31, 2015. In 2008, Exelon management decided to defer indefinitely any share repurchases.