•Employee Stock Purchase Plan ("ESPP"). Purchase rights to purchase common stock are granted to our eligible full and part-time employees, and shares of common stock are issued upon exercise of the purchase rights. An aggregate of 611,265 shares may be issued pursuant to such exercise. The maximum amount that an employee can contribute during a purchase right period is $5,000. The exercise price of a purchase right is the lesser of 100% of the fair market value of a share of common stock on the first day of the purchase right period (the business day preceding January 1) or 85% of the fair market value on the last day of the purchase right period (December 15, or the business day preceding December 15 if December 15 is not a business day).

•2005 Equity Incentive Plan. Key employees and non-employee directors may be granted equity awards, including stock options, restricted stock and restricted stock units ("RSUs"). Options granted before March 6, 2006 vested at 25% on the first anniversary of the grant date, and the balance vests monthly thereafter, such that these options become fully vested no later than four years from the date of grant. These options expire no later than ten years from the date of grant. Options granted on and after March 6, 2006 vest at 25% on each anniversary of the grant date. These options expire no later than eight years from the grant date. RSUs granted to date vest at 25% on each anniversary of the grant date.

•2015 Equity Incentive Plan ("2015 EIP"). Key employees and non-employee directors may be granted equity awards, including stock options, performance share units ("PSUs") and RSUs. Shares issued with respect to awards granted under the 2015 EIP other than stock options or stock appreciation rights, which are referred to as "full value awards", are counted against the 2015 EIP's aggregate share limit as three shares for every share or unit actually issued. No awards have been made under the 2015 Equity Incentive Plan since the adoption of the 2018 Equity Incentive Plan on March 8, 2018 described below.

•2018 Equity Incentive Plan ("2018 EIP"). Key employees and non-employee directors may be granted equity awards, including stock options, PSUs and RSUs. Shares issued with respect to awards granted under the 2018 EIP other than stock options or stock appreciation rights, which are referred to as "full value awards", are counted against the 2018 EIP's aggregate share limit as one share for every share or unit issued. At September 27, 2020, there were 2.5 million shares available for future awards pursuant to the 2018 EIP.


	Fiscal Year Ended
	September 27, 2020		September 29, 2019		September 30, 2018
	(in thousands)
Total stock-based compensation	$	19,424	$	17,618	$	19,582
Income tax benefit related to stock-based compensation	(4,318)		(4,016)		(5,288)
Stock-based compensation, net of tax benefit	$	15,106	$	13,602	$	14,294


	Number of Options (in thousands)	Weighted- Average Exercise Price per Share		Weighted- Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding on September 29, 2019	894	$	33.28

Exercised	(355)	28.63
Forfeited	—	—
Outstanding at September 27, 2020	539	36.34		5.04	$	29,623

Vested or expected to vest at September 27, 2020	539	36.34		5.04	29,623
Exercisable on September 27, 2020	437	34.17		4.62	24,932

The aggregate intrinsic value in the table above represents the total intrinsic value (the difference between our closing stock price on the last trading day of fiscal 2020 and the exercise price, times the number of shares) that would have been received by the in-the-money option holders if they had exercised their options on September 27, 2020. This amount will change based on the fair market value of our stock. At September 27, 2020, we expect to recognize $0.7 million of unrecognized compensation cost related to stock option grants over a weighted-average period of one year.

No stock options were granted in fiscal 2019 and fiscal 2020. The weighted-average fair value of stock options granted during fiscal 2018 was $14.82. The aggregate intrinsic value of options exercised during fiscal 2020, 2019 and 2018 was $22.4 million, $20.4 million and $14.4 million, respectively.

The fair value of our stock options was estimated on the date of grant using the Black-Scholes option pricing model. There were no options granted in fiscal 2020 and 2019. The following assumptions were used in the calculation for fiscal 2018:

For purposes of the Black-Scholes model, forfeitures were estimated based on historical experience. For the fiscal 2018 year-end, we based our expected stock price volatility on historical volatility behavior and current implied volatility behavior. Our risk-free rate of return was based on constant maturity rates provided by the U.S. Treasury. The expected life was based on historical experience.

Net cash proceeds from the exercise of stock options were $10.3 million, $11.8 million and $13.5 million for fiscal 2020, 2019 and 2018, respectively. Our policy is to issue shares from our authorized shares upon the exercise of stock options. The actual income tax benefit realized from exercises of nonqualified stock options and disqualifying dispositions of qualified options for fiscal 2020, 2019 and 2018 was $8.3 million, $6.4 million and $5.1 million, respectively.

RSU awards are granted to our key employee and non-employee directors. The fair value of the RSU was determined at the date of grant using the market price of the underlying common stock as of the date of grant. All of the RSUs have time-based vesting over a four-year period, except that RSUs awarded to directors vest after one year. The total compensation cost of the awards is then amortized over their applicable vesting period on a straight-line basis.

PSU awards are granted to our executive officers and non-employee directors. All of the PSUs are performance-based and vest, if at all, after the conclusion of the three-year performance period. The number of PSUs that ultimately vest is based on 50% growth in our EPS and 50% on our relative total shareholder return over the vesting period. For these performance-based awards, our expected performance is reviewed to estimate the percentage of shares that will vest. The total compensation cost of the awards is then amortized over their applicable vesting period on a straight-line basis.


	RSU			PSU
	Number of Shares (in thousands)	Weighted- Average Grant Date Fair Value per Share		Number of Shares (in thousands)	Weighted- Average Grant Date Fair Value per Share

Nonvested balance at October 1, 2017	511	$	33.19	376	$	36.05
Granted	199	48.16		99	57.40
Vested	(184)	31.85		(270)	31.66
Adjustment (1)	—	—		131	31.66
Forfeited	(38)	36.39		(13)	41.80
Nonvested balance at September 30, 2018	488	39.56		323	44.27
Granted	179	66.26		90	80.41
Vested	(180)	36.95		(108)	31.63
Adjustment (1)	—	—		79	31.63
Forfeited	(17)	48.56		—	—
Nonvested balance at September 29, 2019	470	50.42		384	53.67
Granted	168	83.92		74	99.85
Vested	(178)	46.87		(162)	47.28
Adjustment (1)	—	—		64	48.36
Forfeited	(16)	65.43		(5)	83.98
Nonvested balance at September 27, 2020	444	63.93		355	64.83

(1) For fiscal 2018, includes a payout adjustment of 130,730 PSUs due to the actual performance level achieved for PSUs granted in fiscal 2015 that vested fiscal 2018. For fiscal 2019, includes a payout adjustment of 79,465 PSUs due to the actual performance level achieved for PSUs granted in fiscal 2016 that vested during fiscal 2019. For fiscal 2020 includes a payout adjustment of 63,643 PSUs due to the actual performance level achieved for PSUs granted in fiscal 2017 that vested during fiscal 2020.

During fiscal 2020, 2019 and 2018, we awarded 167,525, 179,478 and 198,960 shares of RSUs, respectively, to our key employees and non-employee directors. The weighted-average grant-date fair value of RSUs granted during fiscal 2020, 2019 and 2018 was $83.92, $66.26 and $48.16, respectively. At September 27, 2020, there were 443,504 RSUs outstanding. RSU forfeitures result from employment terminations prior to vesting. Forfeited shares return to the pool of authorized shares available for award.

During fiscal 2020, 2019 and 2018, we awarded 74,011, 89,816 and 99,217 shares of PSUs, respectively, to our executive officers and non-employee directors. The weighted-average grant-date fair value of PSUs granted during fiscal 2020, 2019 and 2018 was $99.85, $80.41 and $57.40, respectively.

The stock-based compensation expense related to RSUs and PSUs for fiscal 2020, 2019 and 2018 was $17.7 million, $15.4 million and $15.5 million, respectively, and was included in total stock-based compensation expense. At September 27, 2020, there was $27.7 million of unrecognized stock-based compensation costs related to nonvested RSUs and PSUs that will be substantially recognized by the end of fiscal 2022.


	Fiscal Year Ended
	September 27, 2020		September 29, 2019		September 30, 2018
	(in thousands, except for purchase price)
Shares purchased	168		148		141
Weighted-average purchase price per share	$	51.77	$	46.38	$	40.38
Cash received from exercise of purchase rights	$	8,715	$	6,844	$	5,727


	Fiscal Year Ended
	September 27, 2020	September 29, 2019	September 30, 2018
Dividend yield	1.0%	1.0%	1.0%
Expected stock price volatility	26.5%	26.7%	24.0%
Risk-free rate of return, annual	1.6%	2.6%	1.8%
Expected life (in years)	1	1	1

For fiscal 2020, 2019 and 2018, we based our expected stock price volatility on historical volatility behavior and current implied volatility behavior. The risk-free rate of return was based on constant maturity rates provided by the U.S. Treasury. The expected life was based on the ESPP terms and conditions.

Stock-based compensation expense for fiscal 2020, 2019 and 2018 included $1.2 million, $0.9 million and $0.6 million, respectively, related to the ESPP. The unrecognized stock-based compensation costs for awards granted under the ESPP at fiscal 2020 and 2019 year-ends were $0.3 million and $0.2 million, respectively. At September 27, 2020, ESPP participants had accumulated $8.5 million to purchase our common stock.