Our stock compensation plans (collectively, the “Plans”) permit the grant of stock options, stock appreciation rights (“SARs”), performance share units, restricted stock, restricted stock units and other stock-based awards to employees and directors. Our current stock compensation plan, the 2022 Performance Plan, was adopted on April 11, 2022 and expires on February 28, 2032. A total of 21 million shares of our common stock may be issued in respect of grants made under the 2022 Performance Plan. Any shares of common stock that are subject to awards of stock options or SARs will be counted as one share for each share granted for purposes of the aggregate share limit and any shares of common stock that are subject to any other awards will be counted as 2 shares for each share granted for purposes of the aggregate share limit. In addition, shares of common stock that are subject to awards issued under the 2022 Performance Plan or certain prior Plans that expire according to their terms or are forfeited, terminated, canceled or surrendered or are settled, or can be paid, only in cash, or are surrendered in payment of taxes associated with such awards (other than stock options or SARs) will be available for issuance pursuant to a new award under the 2022 Performance Plan. Shares issued under our Plans are usually issued from shares of our common stock held in treasury.

Grants of stock options and SARs (collectively referred to as “options”) under the Plans generally have a graded vesting period of four years whereby one-fourth of the awards vest on each of the first four anniversaries of the grant date, an exercise price equal to the fair market value of one share of our common stock on the date of grant (i.e., the closing market price on that date) and a contractual term of ten years. The exercise of tandem SARs cancels an equivalent number of stock options and, conversely, the exercise of stock options cancels an equivalent number of tandem SARs. Option grants are cancelled on, or 90 days following, termination of employment unless termination is due to retirement, death or disability under certain circumstances, in which case, all outstanding options vest fully and remain outstanding for a term set forth in the related grant agreement.

The following table summarizes the activity related to options during 2023:


	Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value (In millions)
Outstanding at January 1		5,927,398		$	17.20
Options granted		—			—
Options exercised		(329,824	)		10.12			$	1.0
Options expired		(315,118	)		15.69
Options cancelled		(217,641	)		17.48
Outstanding at December 31		5,064,815			17.74		4.5		13.1
Vested and expected to vest at December 31		5,052,481			17.76		4.5		13.0
Exercisable at December 31		3,861,080			20.12		3.9		8.0
Available for grant at December 31		18,710,713

In addition, the aggregate intrinsic value of options exercised in 2022 and 2021 was $0.4 million and $11 million, respectively.

Significant option groups outstanding at December 31, 2023 and related weighted average exercise price and remaining contractual term information follows:


Grant Date	Options Outstanding		Options Exercisable		Exercise Price		Remaining Contractual Term (Years)
2/25/2020		3,110,848		1,907,360	$	10.12		6.16
2/27/2017		511,087		511,087		35.26		3.16
2/22/2016		492,706		492,706		29.90		2.15
2/23/2015		444,806		444,806		27.16		1.15
2/24/2014		338,440		338,440		26.44		0.15
All Other (1)		166,928		166,681
		5,064,815		3,861,080

(1)

Options in the “All Other” category had exercise prices ranging from $22.27 to $32.72. The weighted average exercise price for options outstanding and exercisable in that category was $27.61 for both, while the remaining weighted average contractual term was 1.4 years for both.

Performance share units granted under the Plans are earned over a three-year period beginning January 1 of the year of grant. Total units earned for grants made in 2023, 2022 and 2021 may vary between 0% and 200% of the units granted based on the attainment of performance targets during the related three-year period and continued service. The performance targets are established by the Board of Directors. All of the units earned will be settled through the issuance of an equivalent number of shares of our common stock and are equity classified.

The following table summarizes the activity related to performance share units during 2023:


	Units			Weighted Average Grant Date Fair Value
Unvested at January 1		663,690		$	19.43
Units granted		381,169			11.48
Units vested		(336,402	)		12.85
Units forfeited		—			—
Unvested at December 31		708,457			14.69

We measure the fair value of grants of performance share units based primarily on the closing market price of a share of our common stock on the date of the grant, modified as appropriate to take into account the features of such grants.

Restricted stock units granted under the Plans typically vest over a three-year period beginning on the date of grant. Restricted stock units will be settled through the issuance of an equivalent number of shares of our common stock and are equity classified.

The following table summarizes the activity related to restricted stock units during 2023:


	Units			Weighted Average Grant Date Fair Value
Unvested at January 1		1,374,608		$	12.95
Units granted		1,361,432			11.84
Units vested		(1,270,023	)		11.03
Units forfeited		(63,887	)		13.10
Unvested at December 31		1,402,131			13.60
Units vested but not released		1,884,258			12.24
Outstanding at December 31		3,286,389			14.10

We measure the fair value of grants of restricted stock units based on the closing market price of a share of our common stock on the date of the grant.

Stock-based compensation expense, cash payments made to settle SARs and cash received from the exercise of stock options follows:



(In millions)	2023			2022			2021
Stock-based compensation expense recognized	$	19		$	14		$	36
Tax benefit		(4	)		(3	)		(8	)
After-tax stock-based compensation expense	$	15		$	11		$	28
Cash payments to settle SARs	$	—		$	—		$	—
Cash received from stock option exercises	$	3		$	1		$	26

As of December 31, 2023, unearned compensation cost related to the unvested portion of all stock-based awards was $14 million and is expected to be recognized over the remaining vesting period of the respective grants, through the fourth quarter of 2026.