STOCK-BASED COMPENSATION
At December 31, 2025, there were approximately 715,000 shares of common stock available for future grants under the 1999 Omnibus Plan, as amended and restated effective June 3, 2021, which is the primary stock compensation plan from which broad-based employee, non-employee director, and consultant equity awards may be made.
Stock-based compensation issued under the plans generally consists of restricted stock units, performance share units, and stock options. Performance share units and restricted stock units are payable in shares of the Company's common stock upon vesting. The Company issues shares of its common stock upon the exercise of stock options. The tax benefit related to stock-based compensation was $61 million, $58 million, and $52 million for the years ended December 31, 2025, 2024, and 2023, respectively.
Restricted Stock Units and Performance Share Units
The Company makes broad-based grants of restricted stock units that generally vest during a period of one- to three-years, subject to certain exceptions for terminations other than for "cause," for "good reason," or on account of death or disability. The Company grants performance share units to executives and certain other employees, which generally vest at the end of a three-year period (with the exception of certain shorter-term performance share units), subject to certain exceptions for terminations other than for "cause," for "good reason," or on account of death or disability. The number of shares that ultimately vest depends on achieving certain performance metrics, performance goals, stock price increase and/or relative total shareholder return, as applicable, by the end of the performance period, assuming there is no accelerated vesting for, among other things, a termination of employment under certain circumstances.
Restricted stock units and performance share units granted by the Company during the years ended December 31, 2025, 2024, and 2023 had an aggregate grant-date fair value of $614 million, $635 million, and $586 million, respectively. Restricted stock units and performance share units that vested during the years ended December 31, 2025, 2024, and 2023 had an aggregate fair value at vesting of $1.2 billion, $778 million, and $459 million, respectively. At December 31, 2025, there was $703 million of estimated total future stock-based compensation expense related to unvested restricted stock units and performance share units to be recognized over a weighted-average period of 1.8 years.
The following table summarizes the activity in restricted stock units and performance share units for employees and non-employee directors during the year ended December 31, 2025:
| | | | | | | | | | | | | | | | | | | | | | | | | | |
| | Restricted Stock Units | | Performance Share Units |
| | Shares | | Weighted-average Grant-date Fair Value | | Shares | | Weighted-average Grant-date Fair Value |
Unvested at December 31, 2024 | | 278,723 | | $2,994 | | 200,154 | | $2,779 |
| | | | | | | | |
Granted | | 103,419 | | $4,958 | | 20,113 | | $5,054 |
| Vested | | (148,431) | | $2,807 | | (86,213) | | $2,535 |
Performance shares adjustment (1) | | | | | | 24,256 | | $4,396 |
| Forfeited | | (19,682) | | $3,824 | | (4,221) | | $2,958 |
Unvested at December 31, 2025 | | 214,029 | | $3,996 | | 154,089 | | $3,462 |
(1) Probable outcome for performance-based awards is updated based upon changes in actual and forecasted operating results or expected achievement of performance goals, as applicable, and the impact of modifications, if any.
Stock Options
At December 31, 2025 and 2024, the Company had 5,158 and 15,689 employee stock options outstanding and exercisable, with a weighted-average exercise price of $1,411 per share. The aggregate intrinsic value of employee stock options exercised during the years ended December 31, 2025, 2024, and 2023 was $38 million, $24 million, and $124 million, respectively. No stock options were granted to the executive officers of the Company.