Stock-based compensation expense was $80 million in 2020, $76 million in 2019 and $66 million in 2018. The Company recognized income tax benefits related to stock-based compensation of $17 million in 2020, $19 million in 2019 and $24 million in 2018.

The Company’s equity incentive compensation plan allows for the issuance of various forms of stock-based compensation, including stock options, restricted stock and restricted stock units, including performance-based awards. At December 31, 2020 and 2019, respectively, there were 3,100,665 and 3,742,478 shares available for future grant under the Company’s equity incentive compensation plan.

Stock awards are comprised of restricted stock and restricted stock units. Stock awards granted since 2014 generally vest over three years. Stock awards granted prior to 2014 vested over four years. A portion of stock awards granted after 2013 require a performance condition to be met before such awards vest. The Company may issue shares from treasury stock to the extent available or issue new shares. There were no restricted shares issued in 2020, 2019 or 2018. The number of restricted stock units issued was 480,949 in 2020, 448,487 in 2019 and 348,512 in 2018, with a weighted-average grant date fair value of $81 million, $74 million and $66 million, respectively. Unrecognized

compensation expense associated with restricted stock units was $29 million as of December 31, 2020 and is expected to be recognized over a weighted-average period of approximately one year.

	Restricted Stock Units Outstanding			Weighted- Average Grant Price		Restricted Stock Outstanding			Weighted- Average Grant Price

Unvested at January 1, 2020		691,227		$	171.72		63,591		$	162.45
Granted		480,949			168.71		—			—
Vested		(334,795	)		172.56		(49,468	)		162.48
Cancelled		(20,431	)		171.91		(573	)		158.02
Unvested at December 31, 2020		816,950		$	169.60		13,550		$	162.50

Stock options issued generally vest over three years and are exercisable over terms not exceeding ten years and one day. The Company granted 187,088, 164,244 and 116,852 stock options in 2020, 2019 and 2018, respectively. The Company used an option pricing model to estimate the grant date present value of stock options granted, which was not material in each of 2020, 2019 and 2018.

				Weighted-Average
	Stock Options Outstanding			Exercise Price		Life (In Years)		Aggregate Intrinsic Value (In thousands)

Outstanding at January 1, 2020		305,452		$	170.15
Granted		187,088			173.04
Exercised		(25,047	)		117.81
Expired		(2,070	)		174.09
Outstanding at December 31, 2020		465,423		$	174.11		8.2	$	38
Exercisable at December 31, 2020		133,098		$	178.58		7.4	$	38

For 2020, 2019 and 2018, M&T received $3 million, $9 million and $60 million, respectively, in cash from the exercise of stock options. The intrinsic value of stock options exercised during 2020 was $1 million, compared with $3 million and $16 million in 2019 and 2018, respectively, and the related tax benefits realized by the Company were not material in any of those three years. As of December 31, 2020, the amount of unrecognized compensation cost related to non-vested stock options was not material. The total grant date fair value of stock options vested during 2020, 2019 and 2018 was not material. Upon the exercise of stock options, the Company may issue shares from treasury stock to the extent available or issue new shares.

The stock purchase plan provides eligible employees of the Company with the right to purchase shares of M&T common stock at a discount through accumulated payroll deductions. In connection with the employee stock purchase plan, shares of M&T common stock issued were 77,170 in 2020, 71,676 in 2019 and 58,167 in 2018. As of December 31, 2020, there were 2,233,581 shares available for issuance under the plan. M&T received cash for shares purchased through the employee stock purchase plan of $12 million, $11 million and $10 million in 2020, 2019 and 2018, respectively.

Compensation expense recognized for the stock purchase plan was not material in 2020, 2019 or 2018.

The Company provided a deferred bonus plan pursuant to which eligible employees could elect to defer all or a portion of their annual incentive compensation awards and allocate such awards to several investment options, including M&T common stock. Participants could elect the timing of distributions from the plan. Such distributions are payable in cash with the exception of balances allocated to M&T common stock which are distributable in the form of M&T common stock. Shares of M&T common stock distributable pursuant to the terms of the deferred bonus plan were 14,304 and 16,491 at December 31, 2020 and 2019, respectively. The obligation to issue shares is included in “common stock issuable” in the consolidated balance sheet.

The Company maintains a compensation plan for non-employee members of the Company’s boards of directors that allows such members to receive all or a portion of their compensation in shares of M&T common stock. Through December 31, 2020, 295,182 shares had been issued in connection with the directors’ stock plan.

Through acquisitions, the Company assumed obligations to issue shares of M&T common stock related to deferred directors compensation plans. Shares of common stock issuable under such plans were 3,809 and 5,043 at December 31, 2020 and 2019, respectively. The obligation to issue shares is included in “common stock issuable” in the consolidated balance sheet.