In April 2016, the Company’s Board of Directors and stockholders representing a majority of the Company’s outstanding stock at that time, approved the Monopar Therapeutics Inc. 2016 Stock Incentive Plan, as amended (the “Plan”), allowing the Company to grant up to an aggregate 700,000 shares of stock-based awards in the form of stock options, restricted stock units, stock appreciation rights and other stock-based awards to employees, non-employee directors and consultants. In October 2017, the Company’s Board of Directors voted to increase the stock award pool to 1,600,000 shares of common stock, which subsequently was approved by the Company’s stockholders. In April 2020, the Company’s Board of Directors voted to increase the stock award pool to 3,100,000 (and increase of 1,500,000 shares of common stock), which was approved by the Company’s stockholders in June 2020.

During the three months ended March 31, 2021, the Company’s Plan Administrator Committee (with regards to non-officer employees and consultants) and the Company’s Compensation Committee, as ratified by the Board of Directors (in the case of executive officers and non-employee directors) granted to executive officers, non-officer employees, consultants and non-employee directors aggregate stock options for the purchase of 196,476 shares of the Company’s common stock with exercise prices ranging from $5.76 to $9.67 which vest from one year to four years. All stock option grants have a 10-year term. In addition, an aggregate 124,374 restricted stock units were granted to executive officers, non-officer employees and non-employee directors which vest over one to four years.

Under the Plan, the per share exercise price for the shares to be issued upon exercise of an option shall be determined by the Plan Administrator, except that the per share exercise price shall be no less than 100% of the fair market value per share on the grant date. Fair market value is the Company’s closing price on Nasdaq. Stock options generally expire after 10 years.

Stock option activity under the Plan was as follows:

(1) 196,476 options vest as follows: options to purchase 168,704 shares of the Company’s common stock vest 6/48ths on the six-month anniversary of grant date and 1/48th per month thereafter; options to purchase 17,772 shares of the Company’s common stock vest quarterly over one year; and options to purchase 10,000 shares of the Company’s common stock vest monthly over one year. Exercise prices range from $5.76 to $9.67 per share.

(2) Forfeited options represent unvested shares and vested, expired shares related to employee terminations.

A summary of options outstanding as of March 31, 2021 is shown below:

Restricted stock unit activity under the Plan was as follows:

During the three months ended March 31, 2021 and 2020, the Company recognized $246,343 and $220,765 of employee and non-employee director stock-based compensation expense as general and administrative expenses, respectively, and $111,589 and $100,171 as research and development expenses, respectively. The stock-based compensation expense is allocated on a departmental basis, based on the classification of the stock-based award holder. No income tax benefits have been recognized in the condensed consolidated statements of operations and comprehensive loss for stock-based compensation arrangements.

The Company recognizes as an expense the fair value of options granted to persons (currently consultants) who are neither employees nor non-employee directors. Stock-based compensation expense for consultants which were recorded as research and development expense for the three months ended March 31, 2021 and 2020 was $10,300 and $17,561, respectively.

The fair value of options granted from inception to March 31, 2021 was based on the Black-Scholes option-pricing model assuming the following factors: 4.7 to 6.2 years expected term, 55% to 85% volatility, 0.4% to 2.9% risk free interest rate and zero dividends. The expected term for options granted to date was estimated using the simplified method. There were 196,476 and 163,357 stock options granted during the three months ended March 31, 2021 and 2020, respectively. For the three months ended March 31, 2021 and 2020, the weighted-average grant date fair value was $4.90 and $9.34 per share, respectively. For the three months ended March 31, 2021 and 2020 the fair value of shares vested was $0.3 million and $0.2 million, respectively. At March 31, 2021, the aggregate intrinsic value of outstanding stock options was approximately $3.6 million of which approximately $3.5 million was vested and approximately $0.1 million is expected to vest (representing options to purchase 409,725 shares of the Company’s common stock expected to vest), and the weighted-average exercise price in aggregate was $4.77 which includes $3.49 for fully vested stock options and $8.01 for stock options expected to vest. At March 31, 2021, unamortized unvested balance of stock-based compensation was $3.2 million, to be amortized over 3.0 years.