The Beam Therapeutics Inc. 2017 Stock Option and Grant Plan adopted by the Company’s board of directors in June 2017 and amended in each of February 2019 and May 2019 provided for the grant of qualified incentive stock options and nonqualified stock options, restricted stock awards, restricted stock units, or other awards to the Company’s employees, officers, directors, advisors, and outside consultants for the issuance or purchase of shares of the Company’s common stock.

In October 2019, the Company’s board of directors adopted the Beam Therapeutics Inc. 2019 Equity Incentive Plan, or the 2019 Plan, and, subsequent to the IPO, all equity-based awards are granted under the 2019 Plan. The 2019 Plan provides for the grant of qualified and nonqualified stock options, stock appreciation rights, restricted and unrestricted stock and stock units, performance awards, and other share-based awards to the Company’s employees, officers, directors, advisors, and outside consultants. As of June 30, 2021, the Company had 9,188,648 shares reserved including 2,555,874 shares available for future issuance pursuant to the 2019 Plan.

Stock-based compensation expense recorded as research and development and general and administrative expenses in the condensed consolidated statements of operations and other comprehensive loss is as follows (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Research and development	$	6,340	$	1,805	$	9,495	$	3,578
General and administrative		4,112		964		5,605		1,983
Total stock-based compensation expense	$	10,452	$	2,769	$	15,100	$	5,561

The following table provides a summary of option activity under the Company’s equity award plans:


	Number of options			Weighted average exercise price
Outstanding at December 31, 2020		5,336,441		$	9.70
Granted		1,236,543			86.38
Exercised		(605,509	)		9.65
Forfeitures		(32,731	)		28.84
Outstanding at June 30, 2021		5,934,744			25.58
Exercisable as of June 30, 2021		1,733,868		$	7.48

The weighted-average grant date fair value per share of options granted in the six months ended June 30, 2021 was $57.33. As of June 30, 2021, there was $90.3 million of unrecognized compensation expense related to unvested stock options, which is expected to be recognized over a weighted-average period of approximately 2.5 years.

The Company issues shares of restricted common stock, including both restricted stock units and restricted stock awards. Restricted common stock issued generally vests over a period of two to four years.

The following table summarizes the Company’s restricted stock activity:


	Shares			Weighted- average grant date fair value
Unvested as of December 31, 2020		1,275,338		$	10.95
Issued		619,030			88.49
Vested		(599,207	)		4.44
Cancelled		(4,500	)		80.04
Unvested as of June 30, 2021		1,290,661		$	51.04

At June 30, 2021, there was approximately $62.4 million of unrecognized stock-based compensation expense related to restricted stock that is expected to vest. These costs are expected to be recognized over a weighted-average period of approximately 2.2 years.

In February 2020, the Company’s board of directors adopted the Beam Therapeutics Inc. 2019 Employee Stock Purchase Plan, or ESPP, which was approved by the Company’s stockholders. Pursuant to the ESPP, certain employees of the Company, excluding consultants and non-employee directors, are eligible to purchase common stock of the Company at a reduced rate during offering periods. The ESPP permits participants to purchase common stock using funds contributed through payroll deductions, subject to a calendar year limit of $25,000 and at a purchase price of 85% of the lower of the fair market value of the Company’s common stock on the first trading day of the offering period or on the applicable purchase date, which will be the final trading day of the applicable purchase period. The first offering period is expected to commence on October 1, 2021. As of June 30, 2021, the Company had 1,049,460 shares available for issuance under the ESPP.