Share-Based Compensation (Notes)

6 Months Ended

Jun. 30, 2015

Disclosure of Compensation Related Costs, Share-based Payments

Share-Based Compensation

Stock Benefit Plans

We utilize the Black-Scholes option valuation model for estimating the fair value of our stock options. This model uses a range of assumptions related to volatility, the risk-free interest rate, the expected life, and the dividend yield. The fair values of our stock options are calculated using the following weighted average assumptions for the six months ended June 30, 2015:



	Six Months Ended
Assumptions	June 30, 2015
Dividend yield	1.8	%
Expected volatility	23.3	%
Risk-free interest rate	1.3	%
Expected holding period (in years)	4.0

Stock Options

The following table sets forth stock option activity for the six months ended June 30, 2015:



	Options		Weighted-Average Exercise Price
Outstanding at December 31, 2014	12,107,106		$	11.63
Granted	2,036,010		$	23.00
Exercised	(2,421,740	)	$	11.13
Outstanding at June 30, 2015	11,721,376		$	13.69
Exercisable at June 30, 2015	7,517,834		$	10.33

As of June 30, 2015, the unrecognized compensation expense related to stock options of $12.3 million is expected to be recognized over a weighted average period of 1.5 years.

Restricted Shares

Restricted share activity for the six months ended June 30, 2015 was as follows:



	Restricted Shares		Weighted-Average Grant-Date Fair Value
Nonvested restricted shares at December 31, 2014	1,319,260		$	13.39
Granted	253,791		$	23.00
Vested	(987,684	)	$	12.35
Nonvested restricted shares at June 30, 2015	585,367		$	19.32

As of June 30, 2015, the unrecognized compensation expense related to restricted shares of $9.1 million is expected to be recognized over a weighted average period of 2.0 years.