13. Share-Based Payments

Defined Contribution Plans—Substantially all permanent employees are eligible to participate in defined contribution plans provided by the Company. Under these plans, participants may make contributions into a variety of funds, including a fund that is fully invested in Company stock. Employees are not required to allocate any funds to Company stock. Employees may generally reallocate their account balances on a daily basis; however, employees classified as insiders are restricted under the Company's insider trading policy. Compensation expense relating to these employer contributions under defined contribution plans for fiscal years ended September 30, 2016, 2015 and 2014 was $26.8 million, $13.3 million, and $14.4 million, respectively.

Stock Incentive Plans—Under the 2016 Stock Incentive Plan, the Company has up to 10.9 million securities remaining available for future issuance as of September 30, 2016. Stock options may be granted to employees and non-employee directors with an exercise price not less than the fair market value of the stock on the date of grant. Unexercised options expire seven years after date of grant.

During the three years in the period ended September 30, 2016, option activity was as follows:

	Number of Options (in millions)			Weighted Average Exercise Price
Balance, September 30, 2013		1.6			24.73
Granted		0.6			31.62
Exercised		(0.5	)		23.64
Cancelled		(0.1	)		26.87

Balance, September 30, 2014		1.6			27.69


Granted		—			—
Exercised		(0.3	)		24.98
Cancelled		—			—

Balance, September 30, 2015		1.3			28.26


Granted		—			—
Exercised		(0.4	)		23.96
Cancelled		—			—

Balance, September 30, 2016		0.9			30.36


Exercisable as of September 30, 2014		0.9			25.16


Exercisable as of September 30, 2015		0.7			25.04


Exercisable as of September 30, 2016		0.3			26.99

The following table summarizes information concerning outstanding and exercisable options as of September 30, 2016:

	Options Outstanding								Options Exercisable
	Number Outstanding as of September 30, 2016 (in millions)		Weighted Average Remaining Contractual Life		Weighted Average Exercise Price		Aggregate Intrinsic Value (in millions)		Number Exercisable as of September 30, 2016 (in millions)		Weighted Average Remaining Contractual Life		Weighted Average Exercise Price
Range of Exercise Prices
$24.45 - $27.67		0.2		0.76	$	26.21	$	0.5		0.2		0.76	$	26.21
28.04 - 31.62		0.7		6.72		31.27		0.1		0.1		1.05		28.52

		0.9		5.65		30.36	$	0.6		0.3		0.86		26.99

The remaining contractual life of options outstanding at September 30, 2016 range from 0.76 to 6.72 years and have a weighted average remaining contractual life of 5.65 years. The aggregate intrinsic value of stock options exercised during the years ended September 30, 2016, 2015 and 2014 was $0.6 million, $2.1 million, and $4.3 million, respectively.

The fair value of the Company's employee stock option awards is estimated on the date of grant. The expected term of awards granted represents the period of time the awards are expected to be outstanding. The risk-free interest rate is based on U.S. Treasury bond rates with maturities equal to the expected term of the option on the grant date. The Company uses historical data as a basis to estimate the probability of forfeitures. No stock options were granted during the years ended September 30, 2016 and 2015.

The Company grants stock units to employees under its Performance Earnings Program (PEP), whereby units are earned and issued dependent upon meeting established cumulative performance objectives and vesting over a three-year period. Additionally, the Company issues restricted stock units to employees which are earned based on service conditions. The grant date fair value of PEP awards and restricted stock unit awards is that day's closing market price of the Company's common stock. The weighted average grant date fair value of PEP awards was $29.91, $32.32, and $29.32 during the years ended September 30, 2016, 2015 and 2014, respectively. The weighted average grant date fair value of restricted stock unit awards was $29.82, $31.05, and $29.60 during the years ended September 30, 2016, 2015 and 2014, respectively. Included in the restricted stock unit grants during the twelve months ended September 30, 2015 were 2.6 million restricted stock units with a grant date fair value of $30.04 per share that were converted from unvested URS service based restricted stock awards assumed by the Company in connection with the acquisition of URS. Total compensation expense related to these share-based payments including stock options was $73.4 million, $112.2 million, and $34.4 million during the years ended September 30, 2016, 2015 and 2014, respectively. Included in total compensation expense during the twelve months ended September 30, 2015 was $43.9 million related to the settlement of accelerated URS equity awards with $17.6 million of Company stock and $26.3 million in cash which was classified as acquisition and integration expense. Unrecognized compensation expense related to total share-based payments outstanding as of September 30, 2016 and 2015 was $91.8 million and $115.5 million, respectively, to be recognized on a straight-line basis over the awards' respective vesting periods which are generally three years.

Cash flow attributable to tax benefits resulting from tax deductions in excess of compensation cost recognized for those stock options (excess tax benefits) is classified as financing cash flows. Excess tax benefits of $0.0 million, $3.6 million, and $0.7 million for the years ended September 30, 2016, 2015 and 2014, respectively, have been classified as financing cash inflows in the Consolidated Statements of Cash Flows.