The Company adopted the 2016 Stock Incentive Plan (the “2016 Plan”), effective June 8, 2016, under which 2,000,000 shares of the common stock of the Company, plus the number of shares that remain available for grants of awards under the Company's 2007 Stock Option Plan (the “2007 Plan”) become available as a result of forfeiture, termination, or expiration of awards previously granted under the 2007 Plan, were reserved for the grant of equity awards to its employees, directors and consultants. The equity awards have a maximum term of 7 years at an exercise price of not less than 100% of the fair market value of the Company's common stock on the date the equity award is granted. The 2016 Plan replaced the 2007 Plan.

The 2016 Plan provides for the grant of awards in the form of stock options, stock appreciation rights, restricted stock units (“RSUs”), the vesting of which may be performance-based or service-based, and other rights and benefits. Each RSU issued reduces the number of shares of the Company’s common stock available for grant under the 2016 Plan by two shares. There were no modifications to the 2016 Plan and no awards classified as liabilities in the year ended December 31, 2021.

For the years ended December 31, 2021, 2020 and 2019, the share-based compensation expense was $7.7 million, $5.5 million and $5.9 million, respectively, before provision for income taxes. The Company recorded a tax benefit of approximately $2.1 million, $1.5 million and $1.6 million, respectively, related to the aforementioned share-based compensation expenses. There was no capitalized share-based compensation expense in the years ended December 31, 2021, 2020 and 2019.

As of December 31, 2021, a cumulative total of 8,458,600 shares subject to options have been granted with exercise prices ranging from $3.47 to $40.37. Of these, options have been exercised for the purchase of 6,511,238 shares, while options for 1,672,732 shares have been terminated, and options for 274,630 shares with exercise prices ranging from $24.60 to $40.37 remained outstanding under the stock plans. These options vest over five years and expire seven years after grant. To date, no options have been issued to any of the Company’s non-employee advisors. As of December 31, 2021, 1,414,352 shares remained available for issuance of awards under the stock plans.

A summary of the Company’s option activity and related information for the three years ended December 31, 2021 is as follows:

	Number of options			Weighted- average price		Weighted- average remaining contractual term (in years)		Aggregate intrinsic value (in millions)
Balance at December 31, 2018		845,600		$	28.14
Options granted		—			—
Options exercised		(260,860	)		29.55
Options cancelled/forfeited/expired		(4,600	)		30.59
Balance at December 31, 2019		580,140			29.57
Options granted		—			—
Options exercised		(163,670	)		30.22
Options cancelled/forfeited/expired		(7,060	)		28.95
Balance at December 31, 2020		409,410			29.33
Options granted		—			—
Options exercised		(133,020	)		28.57
Options cancelled/forfeited/expired		(1,760	)		34.57
Balance at December 31, 2021		274,630		$	29.66		1.69	$	13.9
Exercisable at December 31, 2021		261,250		$	29.39		1.66	$	13.3
Expected to vest after December 31, 2021		13,038		$	34.97		2.29	$	0.6

The intrinsic value of stock options at any point in time is calculated as the difference between the exercise price of the underlying awards and the quoted price of the Company’s common stock. The aggregate intrinsic value of options exercised and sold under the Company’s stock option plans was $16.2 million, $11.9 million and $9.1 million for the years ended December 31, 2021, 2020 and 2019, respectively, determined as of the date of option exercise. As of December 31, 2021, there was approximately $0.1 million of total unrecognized compensation cost related to unvested share-based compensation option arrangements granted under the Company’s stock plans, which is expected to be recognized over a weighted-average period of less than one year.

The following table indicates the options outstanding and options exercisable by exercise price with the weighted-average remaining contractual life for the options outstanding and the weighted-average exercise price at December 31, 2021:

	Options Outstanding						Options Exercisable
Exercise price	Number outstanding at December 31, 2021		Weighted-average remaining contractual life (Years)		Weighted-average grant date value		Number exercisable at December 31, 2021		Weighted-average grant date value
$20 – 25		137,585		1.17	$	24.60		137,585	$	24.60
$25 – 30		—		—	$	—		—	$	—
$30 – 35		129,225		2.22	$	34.47		116,865	$	34.46
$35 – 40		6,800		2.00	$	39.19		6,800	$	39.19
$40 – 45		1,020		2.67	$	40.37		—	$	40.37
$20 – 45		274,630		1.69	$	29.66		261,250	$	29.39

The Company utilizes the Black-Scholes option-pricing model to estimate the fair value of share-based compensation at the date of grant, which requires the use of accounting judgment and financial estimates, including estimates of the expected term option holders will retain their vested stock options before exercising them, the estimated volatility of the Company’s stock price over the expected term and the expected number of options that will be forfeited prior to the completion of their vesting requirements. Application of alternative assumptions could produce significantly different estimates of the fair value of share-based compensation amounts recognized in the Consolidated Statements of Income.

The following table summarizes the activity of the Company’s RSUs, which includes service-based and performance-based awards, for the three years ended December 31, 2021:

				Weighted-		Aggregate
				average		intrinsic
	Number			grant date		value
	of shares			fair value		(in millions)
Balance at December 31, 2018		139,510		$	44.73
RSUs granted		83,440			59.98
RSUs vested		(25,862	)		48.31
RSUs cancelled/forfeited/expired		(840	)		59.84
Balance at December 31, 2019		196,248			50.68
RSUs granted		126,540			50.99
RSUs vested		(89,225	)		43.42
RSUs cancelled/forfeited/expired		(7,593	)		57.93
Balance at December 31, 2020		225,970			57.06
RSUs granted		116,326			72.75
RSUs vested		(116,242	)		53.32
RSUs cancelled/forfeited/expired		(8,646	)		52.78
Balance at December 31, 2021		217,408		$	67.63	$	17.4

Performance-based RSUs issued prior to 2018 vest over five years, with 60% of the shares immediately vesting after three years when the performance criteria has been determined to have been met and 20% of the remaining shares vesting annually at the anniversary of the performance determination date, subject to continuous employment of the participant. The performance-based RSU grants issued in 2018 and thereafter vest after three years with 100% of the shares vesting immediately when performance criteria has been determined to have been met. There were 116,989 performance-based RSUs expected to vest as of December 31, 2021. Service based RSUs issued to the Company’s directors generally vest over twelve to fourteen months. Service based RSUs issued to the Company’s management vest over three years. There were 111,631 service-based RSUs expected to vest as of December 31, 2021. No forfeitures are currently expected. The total fair value of RSUs that vested during the years ended December 31, 2021, 2020 and 2019 based on the weighted average grant date values was $6.2 million, $3.9 million and $1.2 million, respectively.

Share-based compensation expense for RSUs for the year ended December 31, 2021, 2020 and 2019 was $7.3 million, $4.6 million and $4.7, respectively. As of December 31, 2021, the total unrecognized compensation expense related to unvested RSUs was $14.8 million and is expected to be recognized over a weighted-average period of 1.4 years.

The McGrath RentCorp Employee Stock Ownership and 401(k) Plan (the “KSOP”) provides that each participant may annually contribute an elected percentage of his or her salary, not to exceed the statutory limit. Each employee who has at least two months of service with the Company and is 21 years or older, is eligible to participate in the KSOP. The Company, at its discretion, may make matching contributions. Contributions are expensed in the year approved by the Board of Directors. Dividends on the Company’s stock held by the KSOP are treated as ordinary dividends and, in accordance with existing tax laws, are deducted by the Company in the year paid. For the year ended December 31, 2021 dividends deducted by the Company were $0.4 million, which resulted in a tax benefit of approximately $0.1 million in 2021.

At December 31, 2021, the KSOP held 245,780 shares, or 1% of the Company’s total common shares outstanding. These shares are included in basic and diluted earnings per share calculations.