Stock-based compensation expense was $111 million in 2022, $85 million in 2021 and $80 million in 2020. The Company recognized income tax benefits related to stock-based compensation of $26 million in 2022, $16 million in 2021 and $17 million in 2020.

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, 2022 and 2021, respectively, there were 1,650,696 and 2,299,502 shares available for future grant under the Company’s equity incentive compensation plan.

Stock awards granted to employees are comprised of restricted stock and restricted stock units. Stock awards generally vest over three years. The Company may issue shares from treasury stock to the extent available or issue new shares. There were no restricted shares issued in 2022, 2021 or 2020. The number of restricted stock units issued was 548,926 in 2022, 636,956 in 2021 and 480,949 in 2020, with a weighted-average grant date fair value of $93 million, $84 million and $81 million, respectively. Unrecognized compensation expense associated with restricted stock and restricted stock units, inclusive of those awards assumed in the acquisition of People's United, was $38 million as of December 31, 2022 and is expected to be recognized over a weighted-average period of approximately one year.

A summary of restricted stock and restricted stock unit activity follows:


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

Unvested at January 1, 2022		1,038,692		$	147.32		4,076		$	162.35
Granted		548,926			169.13		—			—
Assumed in business combination		252,820			164.66		173,204			164.66
Vested		(628,130	)		156.21		(100,017	)		164.57
Cancelled		(44,726	)		155.72		(2,257	)		164.66
Unvested at December 31, 2022		1,167,582			156.23		75,006		$	164.65

Stock options granted to employees generally vest over three years and are exercisable over terms not exceeding ten years and one day. The Company granted 138,825, 178,441 and 187,088 stock options in 2022, 2021 and 2020, respectively. The weighted-average grant date fair value of options granted was $6 million in 2022 and $5 million in each of 2021 and 2020. The Company used an option pricing model to estimate the grant date present value of stock options granted.

A summary of stock option activity follows:


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

Outstanding at January 1, 2022		635,864		$	162.73
Granted		138,825			169.38
Assumed in business combination		1,857,739			141.58
Exercised		(278,336	)		142.36
Expired		(14,030	)		157.47
Outstanding at December 31, 2022		2,340,062		$	148.78		5.9	$	18,797
Exercisable at December 31, 2022		1,840,243		$	147.61		5.2	$	15,797

For 2022, 2021 and 2020 M&T received $37 million, $305,000 and $3 million, respectively, in cash from the exercise of stock options. The intrinsic value of stock options exercised and the related tax benefit realized by the Company were not material in any of those three years. As of December 31, 2022, 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 2022, 2021 and 2020 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 75,232 in 2022, 95,147 in 2021 and 77,170 in 2020. As of December 31, 2022, there were 2,063,202 shares available for issuance under the plan. M&T received cash for shares purchased through the employee stock purchase plan of $11 million in each of 2022 and 2021, and $12 million in 2020. Compensation expense recognized for the stock purchase plan was not material in 2022, 2021 or 2020.

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 11,725 and 13,319 at December 31, 2022 and 2021, respectively. The obligation to issue shares is included in “common stock issuable” in the consolidated balance sheet.

The Company maintains compensation programs for members of the Company’s boards of directors and its regional director advisory councils that provides for a portion of their compensation to be received in shares or restricted stock units. In 2022 and 2021, 22,068 and 28,646 shares, respectively, were granted under such programs.

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 2,306 and 2,450 at December 31, 2022 and 2021, respectively. The obligation to issue shares is included in “common stock issuable” in the consolidated balance sheet.