During each of the three and six months ended June 30, 2024 and 2023, we recognized $8 million, $14 million, $8 million, and $14 million in stock-based compensation expense, which was allocated between cost of goods sold and selling, general and administrative expenses in the condensed consolidated statements of operations. We recognized tax benefits on stock-based compensation of $0 million, $1 million, $1 million and $2 million for the three and six months ended June 30, 2024 and 2023.

A summary of stock option award activity as of and for the six months ended June 30, 2024 is presented below.


Stock Options	Awards (in millions)	Weighted Average Exercise Price		Aggregate Intrinsic Value (in millions)		Weighted Average Remaining Contractual Life (years)
Outstanding at January 1, 2024	0.5	$	28.33

Exercised	(0.2)	$	26.91
Forfeited / Expired (1)	—	$	32.50
Outstanding at June 30, 2024	0.3	$	28.88
Vested and expected to vest at June 30, 2024	0.3	$	28.88	$	2	3.02
Exercisable at June 30, 2024	0.3	$	28.88	$	2	3.02

Cash received by the Company upon exercise of options for the six months ended June 30, 2024 was $4 million. No excess tax benefits or shortfall expenses were recorded related to these exercises.


Restricted Stock Units	Units (in millions)	Weighted Average Fair Value
Outstanding at January 1, 2024	1.3	$	28.71
Granted	0.5	$	32.50
Vested	(0.4)	$	29.06
Forfeited	(0.1)	$	29.80
Outstanding at June 30, 2024	1.3	$	30.10

Tax benefits on the vesting of restricted stock units during the six months ended June 30, 2024 were immaterial.

At June 30, 2024, there was $20 million of unamortized expense relating to unvested restricted stock units that is expected to be amortized over a weighted average period of 1.5 years.


Performance Share Units	Units (in millions)	Weighted Average Fair Value
Outstanding at January 1, 2024	0.8	$	33.20
Granted	0.3	$	38.52
Vested (1)	—	$	29.53
Forfeited	(0.2)	$	30.89
Outstanding at June 30, 2024	0.9	$	35.82

Our performance share units allow for participants to vest in zero to 200% of the targeted number of shares granted. At June 30, 2024, there was $22 million of unamortized expense relating to unvested performance share units that is expected to be amortized over a weighted average period of 2.1 years. The forfeitures include portions of performance share unit grants that were determined to not have vested during the period as a result of not meeting established financial performance thresholds.