In accordance with the 2013 Incentive Plan, stock awards, including stock options and restricted stock, have been granted to certain employees and non-employee directors. Shares of common stock available for distribution to satisfy the grants may consist, in whole or in part, of authorized and unissued shares, treasury shares or shares reacquired by the Company in any manner. Stock-based compensation expense related to stock awards totaled $0.4 million and $0.3 million for the years ended December 31, 2022 and 2021, respectively.

Stock option awards have been granted with an exercise price equal to the market price of the Company’s common stock on the date of the grant and have vesting periods ranging from one to three years, with 10-year contractual terms. The Company recognizes the cost of services received in exchange for stock option awards based on the grant date fair value of the award, with compensation expense recognized on a straight-line basis over the award’s vesting period. The fair value of outstanding awards was determined using the Black-Scholes option pricing model at the date of grant. The Company did not grant any stock option awards during the years ended December 31, 2022 and 2021.

The following table summarizes the Company’s stock option activity for the periods presented.


	Year Ended
	December 31, 2022				December 31, 2021
	Number of Shares		Average Exercise Price		Number of Shares		Average Exercise Price
Options:
Outstanding, beginning of year		420,250	$	9.79		421,000	$	9.79
Granted		—		—		—		—
Exercised		—		—		750		8.23
Forfeited		600		10.86		—		—
Options outstanding, end of year		419,650	$	9.79		420,250	$	9.79
Options exercisable, end of year		416,249	$	9.77		395,678	$	9.74

The aggregate intrinsic value of stock options outstanding (calculated as the amount by which the market value of underlying stock exceeds the exercise price of the option) was approximately $0.1 million as of December 31, 2022 and $0.6 million as of December 31, 2021.

During the years ended December 31, 2022 and 2021, 45,935 shares and 38,430 shares, respectively, of restricted stock were granted. Awards granted to employees had a three-year vesting period, while awards granted to non-employee directors had a one-year vesting period. The Company recognizes the cost of services received in exchange for restricted stock awards based on the grant date closing price of the stock, with compensation expense recognized on a straight-line basis over the award’s vesting period.