STOCK-BASED COMPENSATION

9 Months Ended

Sep. 30, 2017

NOTE 2. STOCK-BASED COMPENSATION

Presented below is a summary of the stock-based compensation cost and associated tax benefit included in the accompanying consolidated statements of operations:

	Three Months Ended				Nine months ended
	September 30,				September 30,
	2017		2016		2017		2016
Stock-based compensation cost	$	31.8	$	23.9	$	88.9	$	72.8
Tax benefit	$	10.3	$	7.8	$	28.8	$	23.7

During the first nine months of 2017, the Company granted 0.2 million employee stock options, which had a weighted average grant date fair value of $30.00 per share based on the Black-Scholes option-pricing model. The Company also granted 1.0 million shares of restricted stock in the first nine months of 2017, which had a weighted average grant date fair value of $113.39 per share. Both the employee stock options and restricted stock generally vest ratably over a four-year period. Additionally, the Company granted approximately 0.2 million shares of performance-based awards whereby the number of shares that ultimately vest are based on the achievement of certain non-market based performance metrics of the Company over a three-year period. The weighted average grant date fair value of these awards was $109.36 per share.

The following weighted average assumptions were used in determining the fair value for options granted in 2017:

Expected dividend yield	1.34%
Expected stock volatility	26.8%
Risk-free interest rate	2.19%
Expected holding period	6.5 years
Grant date fair value	$30.00

Unrecognized compensation expense at September 30, 2017 was $8.0 million and $150.1 million for stock options and unvested restricted stock, respectively, which is expected to be recognized over a weighted average period of 1.4 years and 1.6 years, respectively. Additionally, there was $27.7 million of unrecognized compensation expense relating to the aforementioned non-market based performance-based awards, which is expected to be recognized over a weighted average period of 1.1 years.

The following tables summarize information relating to stock option exercises and restricted stock vesting:

	Nine months ended
	September 30,
Exercise of stock options:	2017		2016
Proceeds from stock option exercises	$	44.0	$	67.7
Aggregate intrinsic value	$	75.7	$	67.8
Tax benefit realized upon exercise	$	26.9	$	23.1
Number of shares exercised		1.0		1.4

	Nine months ended
	September 30,
Vesting of restricted stock:	2017		2016
Fair value of shares vested	$	109.1	$	92.8
Tax benefit realized upon vesting	$	34.6	$	29.5
Number of shares vested		1.0		1.0

	Nine months ended
	September 30,
Vesting of performance-based restricted stock:	2017		2016
Fair value of shares vested	$	19.5	$	23.6
Tax benefit realized upon vesting	$	6.9	$	8.4
Number of shares vested		0.2		0.2

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

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