We have one long-term equity incentive plan, the RadNet, Inc. Equity Incentive Plan, which we first amended and restated April 20, 2015, again on March 9, 2017 and currently as of April 15, 2021 (the "Restated Plan”). The Restated Plan was most recently approved by our stockholders at our annual stockholders meeting on June 10, 2021. We have reserved for issuance under the Restated Plan 16,500,000 shares of common stock. We can issue options (incentive and nonstatutory), performance based options, stock awards (restricted or unrestricted), stock units, performance based stock units, and stock appreciation rights under the Restated Plan.

Stock option grants, whether incentive or nonstatutory, generally vest over 3 to 5 years and expire 5 to 10 years from the date of grant. Under the Restated Plan, stock options may not be granted at a per share exercise price below the fair market value of a share of our common stock on the date of grant, may not be repriced or exchanged without stockholder approval, and the maximum exercisable term of the option may not exceed 10 years.

As of March 31, 2022, we had outstanding options to acquire 683,914 shares of our common stock, of which options to acquire 508,969 shares were exercisable. The following summarizes all of our option transactions for the three months ended March 31, 2022:


Outstanding Options Under the 2006 Plan	Shares	Weighted Average Exercise price Per Common Share		Weighted Average Remaining Contractual Life (in years)	Aggregate Intrinsic Value
Balance, December 31, 2021	473,939	$	9.38
Granted	209,975	29.44


Balance, March 31, 2022	683,914	15.54		6.49	$	6,157,802
Exercisable at March 31, 2022	508,969	11.05		5.43	6,126,246

Aggregate intrinsic value in the table above represents the total pretax intrinsic value (the difference between our closing stock price on March 31, 2022 and the exercise price, multiplied by the number of in-the-money options as applicable) that would have been received by the holder had all holders exercised their options on March 31, 2022. As of March 31, 2022, total unrecognized stock-based compensation expense related to non-vested employee awards was $2.6 million, which is expected to be recognized over a weighted average period of approximately 2.24 years.

During the second quarter of fiscal 2020, in connection with the completion of the DeepHealth acquisition, we granted options to acquire 412,434 shares at a grant date fair value of $16.93 per share unit to DeepHealth employees in replacement of their stock options that were outstanding as of the closing date. As of March 31, 2022, total unrecognized stock based compensation expense related to non-vested DeepHealth options was approximately $1.6 million, which is expected to be recognized over a weighted average period of approximately 1.23 years


Outstanding Options Under the Deep Health Plan	Shares	Weighted Average Exercise price Per Common Share		Weighted Average Remaining Contractual Life (in years)	Aggregate Intrinsic Value
Balance December 31, 2021	320,660	$	—
Exercised	(12,637)	—
Balance, March 31, 2022	308,023	—		7.18	$	6,890,475
Exercisable at March 31, 2022	46,912	—		7.18	1,049,413

Options issued in replacement of original DeepHealth options as a result of our acquisition are not included in the share count under the Restated Plan.

The Restated Plan permits the award of restricted stock awards (“RSA’s”). As of March 31, 2022, we have issued a total of 7,743,651 RSA’s of which 438,786 were unvested at March 31, 2022. The following summarizes all unvested RSA’s activities during the three months ended March 31, 2022:


	RSA's	Weighted-Average Remaining Contractual Term (Years)	Weighted-Average Fair Value
RSA's unvested at December 31, 2021	456,075		$	20.06
Changes during the period
Granted	500,622		$	28.72
Vested	(517,911)		$	21.63

RSA's unvested at March 31, 2022	438,786	1.16	$	25.96

The Restated Plan also permits share awards not subject to any future service period. These are valued and expensed based on the closing price of our common stock on the date of award. During the three months ended March 31, 2022, no such awards were granted.

In January 2022, the company granted certain employees PSUs with a target award of 25,683 shares of our common stock. The PSUs will vest in two equal parts, starting three years from the grant date based on continuous service, with the number of shares earned (0% to 200% of the target award) depending upon the extent to which we achieve a performance condition as determined by the board of directors over the period from January 1, 2022 through December 31, 2022.

In January 2022, the company granted certain employees PSOs with a potential to option a maximum of 111,925 shares of our common stock. The PSOs will vest in three equal parts, starting three years from the grant date based on continuous service, with the number of shares earned (0 shares to 111,925 shares) depending upon the extent to which we achieve a performance condition as determined the board of directors over the period from January 1, 2022 through December 31, 2022.

In summary, of the 16,500,000 shares of common stock reserved for issuance under the Restated Plan, at March 31, 2022, there remain 2,380,364 shares available under the Restated Plan for future issuance.