The Company maintains the MarketAxess Holdings Inc. 2020 Equity Incentive Plan (the “2020 Plan”), which provides for the grant of restricted stock, restricted stock units, performance shares, performance stock units (collectively, “full value awards”), stock options and other stock-based awards as incentives to encourage employees, consultants and non-employee directors to participate in the long-term success of the Company. As of March 31, 2024, there were 2,330,396 shares available for grant under the 2020 Plan.

Total stock-based compensation expense was as follows:


	Three Months Ended March 31,
	2024		2023
	(In thousands)
Employees	$	6,893	$	7,100
Non-employee directors		405		388
Total stock-based compensation	$	7,298	$	7,488

The Company records stock-based compensation expense for employees in employee compensation and benefits and for non-employee directors in general and administrative expenses in the Consolidated Statements of Operations. Included in the stock-based compensation for employees in the table above is $0.2 million of capitalized software development costs for each of the three months ended March 31, 2024 and 2023.

During the three months ended March 31, 2024, the Company granted (i) 126,965 restricted stock units, (ii) 20,793 stock options and (iii) performance stock units with an expected pay-out at target of 30,811 shares of common stock. The fair values of the restricted stock units and performance stock units were based on a weighted-average fair value per unit at the grant date of $220.89 and $220.50, respectively. Based on the Black-Scholes option pricing model, the weighted-average fair value for each stock option granted was $77.16 per share.

As of March 31, 2024, the total unrecognized compensation cost related to all non-vested awards was $68.0 million. That cost is expected to be recognized over a weighted-average period of 2.4 years.

The Company maintains the MarketAxess Holdings Inc. 2022 Employee Stock Purchase Plan (the “ESPP”), pursuant to which a total of 121,221 shares of the Company’s Common Stock is available for purchase by employees. The Company issued 3,756 shares of common stock on February 15, 2024 under the ESPP. As of March 31, 2024, there were 112,810 shares available for purchase under the ESPP.