Share-Based Compensation | 9. Share-Based Compensation Our share-based compensation consists of stock options, restricted stock units (“RSU”), and performance stock units (“PSU”). We also offer an employee stock purchase plan. Under the 2013 Ceridian HCM Holding Inc. Stock Incentive Plan, as amended ("2013 SIP") and Ceridian HCM Holding Inc. 2018 Equity Incentive Plan (as amended and restated from time to time, the “2018 EIP”), we have shares reserved for issuance of common stock to eligible employees and our Board of Directors. The 2018 EIP serves as a successor to the 2013 SIP as we ceased granting awards under the 2013 SIP as of April 24, 2018, and we do not intend to grant any additional awards under the 2013 SIP. Most of our equity awards under the 2018 EIP vest either annually or quarterly on a pro rata basis, generally over a one -, three -, four -, or five-year period or on a specific date if certain performance criteria are satisfied and certain equity values are attained. In addition, upon termination of service, all vested awards must be exercised generally within 90 days after termination, or these awards will be forfeited. The equity awards have a 10 -year contractual term, and the options have an exercise price that is not less than the fair market value of the underlying stock on the date of grant. As of March 31, 2023 , there were 804,308 stock options and RSUs outstanding under the 2013 SIP and there were 12,727,310 stock options, RSUs, and PSUs outstanding and 11,759,391 shares available for future grants of equity awards under the 2018 EIP. Total share-based compensation expense was $ 40.2 million and $ 35.5 million for the three months ended March 31, 2023, and 2022, respectively. Performance-Based Stock Options Performance-based stock option activity was as follows: Shares Weighted Weighted Aggregate Outstanding at December 31, 2022 1,760,438 $ 66.10 7.4 $ 0.1 Granted — — — — Exercised ( 2,857 ) ( 49.72 ) — — Forfeited or expired — — — — Outstanding at March 31, 2023 1,757,581 $ 65.23 7.1 $ 14.0 Exercisable at March 31, 2023 257,581 $ 65.06 7.3 $ 2.1 As of March 31, 2023 , there was $ 0.8 million of share-based compensation expense related to unvested performance-based stock option awards not yet recognized, which is expected to be recognized over a weighted-average period of 0.1 year. Performance Stock Units PSU activity was as follows: Shares Outstanding at December 31, 2022 706,467 Granted 651,122 Vested and released ( 247,603 ) Forfeited or canceled ( 114,562 ) Outstanding at March 31, 2023 995,424 Releasable at March 31, 2023 101,380 On February 28, 2023, we granted PSUs under the 2023 Ceridian HCM Holding, Inc. Management Incentive Plan (the “2023 MIP”) for the incentive period of January 1, 2023 through December 31, 2023, and also as part of long term incentive grants to certain members of management. The vesting conditions for the PSUs are primarily based on key financial metrics and the probability of vesting will continue to be evaluated throughout 2023, and share-based compensation will be recognized in accordance with that probability. As of March 31, 2023 , there was $ 50.7 million of share-based compensation expense related to unvested PSUs not yet recognized. Restricted Stock Units RSU activity was as follows: Shares Outstanding at December 31, 2022 2,890,817 Granted 1,506,681 Vested and released ( 556,143 ) Forfeited or canceled ( 59,560 ) Outstanding at March 31, 2023 3,781,795 Releasable at March 31, 2023 712,279 As of March 31, 2023 , there was $ 187.8 million of share-based compensation expense related to unvested RSUs not yet recognized, which is expected to be recognized over a weighted-average period of 1.9 years. Term-Based Stock Options Term-based stock option activity was as follows: Shares Weighted Weighted Aggregate Outstanding at December 31, 2022 7,296,086 $ 50.59 6.4 $ 117.4 Granted — — — — Exercised ( 280,971 ) ( 40.29 ) — — Forfeited or expired ( 18,335 ) ( 59.03 ) — — Outstanding at March 31, 2023 6,996,780 $ 50.98 6.2 $ 164.1 Exercisable at March 31, 2023 5,887,425 $ 46.85 6.0 $ 158.6 As of March 31, 2023 , there was $ 23.0 million of share-based compensation expense related to unvested term-based stock options not yet recognized, which is expected to be recognized over a weighted-average period of 0.5 year. Global Employee Stock Purchase Plan We maintain the Ceridian HCM Holding Inc. Global Employee Stock Purchase Plan (“GESPP”) pursuant to which we have shares reserved for the issuance of common stock to eligible participants through quarterly purchases via payroll deductions. A total of 1,596,174 shares of common stock are available for future issuances under the plan as of March 31, 2023 . The purchase price is the lower of 85 % of the fair market value of a share of common stock on (i) January 1 or (ii) the purchase date. Our GESPP activity was as follows: Period Ended Shares Issued Purchase Price March 31, 2023 62,584 $ 62.24 |