As of March 31, 2025, the Company’s stock-based compensation consisted of restricted stock units and employee stock purchase plan. Stock-based compensation expense for the following periods were:


In millions	Three months ended March 31
	2025		2024
Restricted stock units	$	8	$	10

Employee stock purchase plan	1		1
Stock-based compensation expense	9		11
Tax expense (benefit)	2		(1)
Stock-based compensation expense (net of tax)	$	11	$	10

Stock-based compensation expense is recognized in the Condensed Consolidated Financial Statements based upon fair value.

On March 3, 2025, the Company granted market-based restricted stock units vesting on March 3, 2028. The fair value of the awards was determined based on the grant date fair value and will be recognized over the requisite service period.

The table below details the significant assumptions used in determining the fair value of the market-based restricted stock units granted on March 3, 2025:

Expected volatility for these restricted stock units is calculated as the historical volatility of the Company’s stock over a period of approximately three years, as management believes this is the best representation of prospective trends. The risk-free interest rate was determined based on a three year U.S. Treasury yield curve in effect at the time of the grant.

As of March 31, 2025, the total unrecognized compensation cost of $85 million related to unvested restricted stock grants is expected to be recognized over a weighted average period of approximately 2.4 years under the endpoint method. As of March 31, 2025, all stock option grants have vested.

Employee Stock Purchase Plan The Company’s Employee Stock Purchase Plan (“ESPP”) provides employees a 15% discount on stock purchases using a three-month look-back feature where the discount is applied to the stock price that represents the lower of the Company’s closing stock price on either the first day or the last day of each calendar quarter. Participants can contribute between 1% and 10% of their compensation.