PSUs until the issuance of the shares of common stock. Dividends are accrued by the Company and will be paid once the PSUs contingent on the achievement of performance conditions vest.
In the nine months ended September 30, 2021, to satisfy employees’ tax obligations upon the vesting of performance stock, the Company purchased 9,982 shares of common stock totaling $0.9 million as the result of the vesting of 29,468 shares of performance stock.
As of September 30, 2021, there were $32.8 million in total unrecognized compensation costs related to restricted stock, restricted stock units, and performance stock units. These costs are expected to be recognized over a weighted average period of 1.9 years.
Employee Stock Purchase Plan
In May 2018, the Company’s stockholders approved an Employee Stock Purchase Plan, (“ESPP”), under which a total of 750,000 shares of the Company’s common stock will be made available for purchase to employees. The ESPP is a broad-based plan that permits employees to contribute up to 10% of wages and base salary to purchase shares of the Company’s common stock at a discount, subject to applicable annual Internal Revenue Service limitations. Under the ESPP, a participant may not purchase more than a maximum of 312 shares of the Company’s common stock during any single offering period. No participant may accrue options to purchase shares of the Company’s common stock at a rate that exceeds $25,000 in fair market value of the Company’s common stock (determined at the time such options are granted) for each calendar year in which such rights are outstanding at any time. The exercise price per share of common stock shall be 90% (for eligible U.S. employees) or 85% (for eligible international employees) of the lesser of the fair value of the stock on the first day of the applicable offering period or the applicable exercise date.
The Company records compensation expense over the offering period related to the discount that is given to employees, which totaled $0.1 million and $18.6 thousand for the three months ended September 30, 2021 and 2020, and $0.3 million and $0.2 million for the nine months ended September 30, 2021 and 2020. As of September 30, 2021, 655,112 shares were reserved for future issuance under the ESPP.
18. EQUITY
Common Stock
The Company’s common stock is listed on Cboe BZX under the trading symbol CBOE. As of September 30, 2021, 325,000,000 shares of the Company’s common stock were authorized, $0.01 par value, and 126,226,121 and 106,642,977 shares were issued and outstanding, respectively. As of December 31, 2020, 325,000,000 shares of the Company’s common stock were authorized, $0.01 par value, and 125,998,967 and 107,299,933 shares were issued and outstanding, respectively. The holders of common stock are entitled to one vote per share.
Common Stock in Treasury, at Cost
The Company accounts for the purchase of treasury stock under the cost method with the shares of stock repurchased reflected as a reduction to Cboe stockholders’ equity and included in common stock in treasury, at cost in the condensed consolidated balance sheets. Shares repurchased under the Company’s share repurchase program are available to be redistributed. When treasury shares are redistributed, they are recorded at the average cost of the treasury shares acquired. The Company held 19,583,144 and 18,699,034 shares of common stock in treasury as of September 30, 2021 and December 31, 2020, respectively.
Share Repurchase Program
In 2011, the board of directors approved an initial authorization for the Company to repurchase shares of its outstanding common stock of $100 million and approved additional authorizations of $100 million in each of 2012, 2013, 2014, 2015 and 2016, $250 million in each of 2018, 2019 and 2020, and $200 million in February 2021, for a total authorization of $1.6 billion. The Company expects to fund repurchases primarily through the use of existing cash balances. The program permits the Company to purchase shares, through a variety of methods, including in the open market or through privately negotiated transactions, in accordance with applicable securities laws. It does not obligate the Company to make any repurchases at any specific time or situation.