Share-Based Compensation Plans

The following table summarizes share-based compensation expense recognized in the Consolidated Statements of Income in Compensation and benefits (in millions):



Years ended December 31	2015		2014		2013
Restricted share units ("RSUs")	$	201	$	187	$	174
Performance share awards ("PSAs")	127		132		117
Share options	—		—		2
Employee share purchase plans	11		9		7
Total share-based compensation expense	339		328		300
Tax benefit	95		94		81
Share-based compensation expense, net of tax	$	244	$	234	$	219

Restricted Share Units

RSUs generally vest between three and five years. The fair value of RSUs is based upon the market value of Aon ordinary shares at the date of grant. With certain limited exceptions, any break in continuous employment will cause the forfeiture of all non-vested awards. Compensation expense associated with RSUs is recognized on a straight-line basis over the requisite service period. Dividend equivalents are paid on certain RSUs, based on the initial grant amount.

A summary of the status of the Company's RSUs is as follows (shares in thousands):



Years ended December 31	2015				2014				2013
	Shares		Fair Value (1)		Shares		Fair Value (1)		Shares		Fair Value (1)
Non-vested at beginning of year	8,381		$	63	9,759		$	51	10,432		$	44
Granted	2,459		97		2,844		84		3,714		62
Vested	(3,385	)	58		(3,732	)	49		(3,945	)	44
Forfeited	(288	)	71		(490	)	58		(442	)	47
Non-vested at end of year	7,167		77		8,381		63		9,759		51


(1)	Represents per share weighted average fair value of award at date of grant.

The fair value of RSUs that vested during 2015, 2014 and 2013 was $196 million, $183 million and $172 million, respectively.

Performance Share Awards

The vesting of PSAs is contingent upon meeting a cumulative level of earnings per share performance over a three-year period. The actual issue of shares may range from 0-200% of the target number of PSAs granted, based on the terms of the plan and level of achievement of the related performance target. The grant date fair value of PSAs is based upon the market price of an Aon ordinary share at the date of grant. The performance conditions are not considered in the determination of the grant date fair value for these awards. Compensation expense is recognized over the performance period based on management's estimate of the number of units expected to vest. Management evaluates its estimate of the actual number of shares expected to be issued at the end of the programs on a quarterly basis. The cumulative effect of the change in estimate is recognized in the period of change as an adjustment to Compensation and benefits expense, if necessary. Dividend equivalents are not paid on PSAs.

Information regarding the Company's target PSAs granted and shares that would be issued at current performance levels for PSAs granted during the years ended December 31, 2015, 2014 and 2013, respectively, is as follows (shares in thousands, dollars in millions, except fair value):



	2015		2014		2013
Target PSAs granted	993		816		1,135
Weighted average fair value per share at date of grant	$	96	$	81	$	58
Number of shares that would be issued based on current performance levels	982		1,591		2,191
Unamortized expense, based on current performance levels	$	67	$	45	$	—

During 2015, the Company issued approximately 1.6 million shares in connection with performance achievements related to the 2012 Leadership Performance Plan ("LPP") cycle. During 2014, the Company issued approximately 0.8 million shares in connection with performance achievements related to the 2011 LPP cycle and 0.2 million shares related to other performance plans. During 2013, the Company issued approximately 0.6 million shares in connection with performance achievements related to the 2010 LPP cycle and 0.1 million shares related to other performance plans.

Share Options

The Company did not grant any share options for the years ended December 31, 2015, 2014 and 2013.

A summary of the status of the Company's share options and related information is as follows (shares in thousands):



Years ended December 31	2015				2014				2013
	Shares		Weighted-Average Exercise Price Per Share		Shares		Weighted-Average Exercise Price Per Share		Shares		Weighted-Average Exercise Price Per Share
Beginning outstanding	2,300		$	32	3,462		$	32	5,611		$	32
Granted	—		—		—		—		—		—
Exercised	(1,450	)	27		(1,155	)	33		(2,116	)	32
Forfeited and expired	(13	)	39		(7	)	37		(33	)	34
Outstanding at end of year	837		40		2,300		32		3,462		32
Exercisable at end of year	837		40		2,273		32		3,270		32
Shares available for grant	12,179				16,333				11,330

A summary of options outstanding and exercisable as of December 31, 2015 is as follows (shares in thousands):



	Options Outstanding				Options Exercisable
Range of Exercise Prices	Shares Outstanding	Weighted-Average Remaining Contractual Life (years)	Weighted-Average Exercise Price Per Share		Shares Exercisable	Weighted-Average Remaining Contractual Life (years)	Weighted-Average Exercise Price Per Share
19.54 - 25.51	79	2.18	$	20.18	79	2.18	$	20.18
25.52 - 32.53	25	1.93	29.15		25	1.93	29.15
32.54 - 36.88	160	1.14	35.77		160	1.14	35.77
36.89 - 43.44	247	3.12	39.32		247	3.12	39.32
43.45 - 52.93	326	2.46	48.26		326	2.46	48.26
	837				837

The aggregate intrinsic value represents the total pretax intrinsic value, based on options with an exercise price less than the Company's closing share price of $92.21 as of December 31, 2015, which would have been received by the option holders had those option holders exercised their options as of that date. At December 31, 2015, the aggregate intrinsic value of options outstanding was $44 million, of which $44 million was exercisable.

Other information related to the Company's share options is as follows (in millions):



	2015		2014		2013
Aggregate intrinsic value of stock options exercised	$	104	$	61	$	73
Cash received from the exercise of stock options	40		38		61
Tax benefit realized from the exercise of stock options	36		16		15

Unamortized deferred compensation expense, which includes both options and RSUs, amounted to $378 million as of December 31, 2015, with a remaining weighted-average amortization period of approximately 2.1 years.

Employee Share Purchase Plan

United States

The Company has an employee share purchase plan that provides for the purchase of a maximum of 7.5 million shares of the Company's ordinary shares by eligible U.S. employees. The Company's ordinary shares were purchased at 6-month intervals at 85% of the lower of the fair market value of the ordinary shares on the first or last day of each 6-month period. In 2015, 2014, and 2013, 411,636 shares, 439,000 shares and 556,000 shares, respectively, were issued to employees under the plan. Compensation expense recognized was $9 million in 2015, $7 million in 2014, and $6 million in 2013.

United Kingdom

The Company also has an employee share purchase plan for eligible U.K. employees that provides for the purchase of shares after a 3-year period and that is similar to the U.S. plan previously described. Three-year periods began in 2015, 2014, 2013, allowing for the purchase of a maximum of 100,000, 300,000, and 350,000 shares, respectively. In 2015, 2014, and 2013, 2,779 shares, 642 shares, and 172,110 shares, respectively, were issued under the plan. Compensation expense of $2 million was recognized in 2015 and 2014, as compared to $1 million of compensation expense in 2013.