On June 9, 2020, our stockholders approved amendments to our Restated Certificate of Incorporation to effect a reverse stock split of our shares of common stock, and our Board approved a final reverse stock split ratio of 1-for-20 and a corresponding reduction in the number of authorized shares of our common stock. The reverse stock split became effective on June 10, 2020. Accordingly, the number of shares, equity awards, and income (loss) per share disclosed throughout this Quarterly Report on Form 10-Q have been retrospectively adjusted to reflect the reverse stock split for all prior periods presented.

Pursuant to our restated certificate of incorporation, as of March 31, 2021, the Board had the authority to issue up to a total of 100,500,000 shares of common stock. Each holder of common stock is entitled to one vote per share on any matter that is submitted to a vote of stockholders. In addition, holders of our common stock will vote as a single class of stock on any matter that is submitted to a vote of stockholders.

In May 2018, the Board authorized us to repurchase up to $300.0 million of our common stock under our share repurchase program. During the three months ended March 31, 2021 and 2020, we did not purchase any shares under the program. As of March 31, 2021, up to $245.0 million of common stock remained available for purchase under our program. The timing and amount of share repurchases, if any, will be determined based on market conditions, limitations under the Amended Credit Agreement, share price, available cash and other factors, and the share repurchase program may be terminated at any time.

The Groupon, Inc. Stock Plans (the "Plans") are administered by the Compensation Committee of the Board (the "Compensation Committee"). As of March 31, 2021, 3,212,132 shares of common stock were available for future issuance under the Plans.

The stock-based compensation expense related to stock awards issued under the Plans are presented within the following line items of the condensed consolidated statements of operations for the three months ended March 31, 2021 and 2020 (in thousands):


	Three Months Ended March 31,
	2021		2020
Cost of revenue	$	171	$	259
Marketing	135		874
Selling, general and administrative	6,873		12,882
Total stock-based compensation expense	$	7,179	$	14,015

We capitalized $0.9 million and $1.1 million of stock-based compensation for the three months ended March 31, 2021 and 2020 in connection with internally-developed software and cloud computing arrangements.

The Groupon, Inc. 2012 Employee Stock Purchase Plan, as amended, ("ESPP") authorizes us to grant up to 1,000,000 shares of common stock under that plan as of March 31, 2021. For the three months ended March 31, 2021 and 2020, 23,418 and 28,621 shares of common stock were issued under the ESPP.

The restricted stock units granted under the Plans generally have vesting periods between one and four years and are amortized on a straight-line basis over their requisite service period.


	Restricted Stock Units	Weighted-Average Grant Date Fair Value (per unit)
Unvested at December 31, 2020	1,853,007	$	31.91
Granted	129,827	32.87
Vested	(222,244)	27.60
Forfeited	(125,053)	32.39
Unvested at March 31, 2021	1,635,537	$	32.37

As of March 31, 2021, $31.4 million of unrecognized compensation costs related to unvested restricted stock units are expected to be recognized over a remaining weighted-average period of 0.94 years.

We grant performance share units under the Plans that vest in shares of our common stock upon the achievement of financial and operational targets specified in the respective award agreement ("Performance Share Units"). During the year ended December 31, 2019, we also granted performance share units subject to a market condition ("Market-based Performance Share Units").

Our Performance Share Units and Market-based Performance Share Units are subject to continued employment through the performance period dictated by the award and certification by the Compensation Committee that the specified performance conditions have been achieved.


	Performance Share Units	Weighted-Average Grant Date Fair Value (per unit)		Market-based Performance Share Units	Weighted-Average Grant Date Fair Value (per unit)
Unvested at December 31, 2020	124,709	$	29.73	57,668	$	60.60
Granted (1)	41,729	15.44		—	—
Vested	(86,710)	24.36		—	—
Forfeited	(282)	69.00		—	—
Unvested at March 31, 2021	79,446	27.95		57,668	60.60

Maximum shares issuable upon vesting at March 31, 2021	79,446			57,668

(1)Performance Share Units granted during the three months ended March 31, 2021 relate to the issuance of incremental shares upon the Compensation Committee's certification of the achievement of the 2020 performance metrics.