The Company has outstanding stock options assumed from acquisitions. A summary of the status of, and changes in, the Company's stock option awards for the three months ended March 31, 2022, follows:

Under the terms of the 2020 Equity Plan, the Company has granted RSU, PSU, and DSU awards. Upon vesting/delivery, shares are expected (though not required) to be issued from treasury.

The Company grants RSUs to members of management periodically throughout the year. Each RSU is equivalent to one share of the Company’s common stock. These units have requisite service periods ranging from one to five years, subject to accelerated vesting upon eligible retirement from the Company. Recipients earn quarterly dividend equivalents on their respective units which entitle the recipients to additional units. Therefore, dividends earned each quarter compound based upon the updated unit balances.

The Company also grants PSU awards to members of management periodically throughout the year. Each PSU is equivalent to one share of the Company’s common stock. The number of units that ultimately vest will be determined based on the achievement of the market or other performance goals, subject to accelerated service-based vesting conditions upon eligible retirement from the Company.

The Company grants DSUs, which are restricted stock units with a deferred settlement date, to its directors and advisory directors. Each DSU is equivalent to one share of the Company’s common stock. DSUs vest over a one-year period following the grant date. These units generally are subject to the same terms as RSUs under the 2020 Equity Plan, except that, following vesting, settlement occurs within 30 days following the earlier of separation from the board or a change in control of the Company. After vesting and prior to delivery, these units will continue to earn dividend equivalents.

A summary of changes in the Company’s RSU, PSU, and DSU awards for the three months ended March 31, 2022, is as follows:

(1)

Shares for PSU awards represent target shares at grant date.

On March 23, 2022, under the terms of the 2020 Equity Plan, the Company granted 156,483 RSUs to members of management. The grant date fair value of the award totaled $4.0 million and will be recognized as compensation expense over the requisite service period ranging from one year to five years. The terms of these awards included an accelerated vesting provision upon eligible retirement from the Company, after a one-year minimum requisite service period. Subsequent to the requisite service period, the awards will become 100% vested.

On March 23, 2022, the Company granted a target of 78,233 market-based PSUs with a maximum award of 125,173 units. The actual number of units issued at the vesting date could range from 0% to 160% of the initial grant, depending on attaining a market-based total shareholder return performance goal. The grant date fair value of the award is estimated to be $2.0 million and will be recognized in compensation expense over the performance period ending December 31, 2024. The Company expects to finalize the grant date fair value of these awards in the second quarter of 2022.

On March 23, 2022, the Company granted a target of 78,233 performance-based PSUs with a maximum award of 125,173 units. The actual number of units issued at the vesting date could range from 0% to 160% of the initial grant, depending on attaining a core return on average tangible common equity performance goal. The grant date fair value of the award is $2.0 million and will be recognized in compensation expense over the performance period ending December 31, 2024, subject to achievement of the performance goal.

Further, on March 23, 2022, the Company granted a target of 38,774 PSUs with a maximum award of 77,548 units. The actual number of units issued at the vesting date could range from 0% to 200% of the initial grant, depending on attaining a performance goal based upon the compounded annual revenue growth rate of the FirsTech operating segment. The grant date fair value of the award is $1.0 million and will be recognized in compensation expense over the performance period ending December 31, 2024, subject to achievement of the performance goal.

On March 23, 2022, the Company granted 32,658 DSUs to directors and advisory directors. The grant date fair value of the award totaled $0.8 million and will be recognized as compensation expense over the requisite service period of one year. Subsequent to the requisite service period, the awards will become 100% vested.

2021 Employee Stock Purchase Plan

The First Busey Corporation 2021 ESPP was approved at the Company’s 2021 Annual Meeting of Stockholders and details can be found within First Busey’s Definitive Proxy Statement filed with the SEC on April 8, 2021. The plan initially reserved for issuance and purchase an aggregate of 600,000 shares of the Company’s common stock. The purpose of the 2021 ESPP is to provide a means through which our employees may acquire a proprietary interest in the Company by purchasing shares of our common stock at a 15% discount through voluntary payroll deductions, to assist us in retaining the services of our employees and securing and retaining the services of new employees, and to provide incentives for our employees to exert maximum efforts toward our success. The first offering under this plan began on July 1, 2021.

Stock-based Compensation Expense

The Company did not record any stock option compensation expense for the three months ended March 31, 2022, or 2021. As of March 31, 2022, the Company did not have any unrecognized stock option expense.

The Company recognized compensation expense related to nonvested RSU, PSU, and DSU awards, as well as the 2021 ESPP, as summarized in the table below (dollars in thousands):


	Three Months Ended March 31,
	2022		2021
Stock-based compensation expense
RSU awards	$	1,176	$	1,230
PSU awards		412		60
DSU awards		226		158
2021 ESPP		95		—
Total stock-based compensation expense	$	1,909	$	1,448

Unamortized compensation expense related to nonvested RSU, PSU, and DSU awards is summarized in the table below (dollars in thousands):


	As of
	March 31,			December 31,
	2022			2021
Unamortized stock-based compensation
RSU awards	$	12,838		$	10,204
PSU awards		5,544			1,547
DSU awards		825			209
Total unamortized stock-based compensation	$	19,207		$	11,960

Weighted average period over which expense is to be recognized		2.9	yrs		2.9	yrs

Shares Available for Issuance Under Stock-based Compensation Plans

Shares remaining available for issuance pursuant to authorized stock-based compensation plans as of March 31, 2022, were as follows:


	Shares Remaining
	Available for Issuance
	Pursuant to the Plan
2020 Equity Plan		643,569
2021 Employee Stock Purchase Plan		544,470