In February 2018, the Company enacted a deferral of release of all vested restricted stock units and performance share units granted prior to February 2018. The Company did not recognize compensation cost in connection with certain awards for which the grant date was achieved. The deferral of release impacted only 2018 restricted stock units and performance share units and was intended to prevent the release of unregistered shares to grantees. During the deferral period, a grantee retained the legal right to the awards they had vested in, but the Company deferred the release of the underlying shares until it could become current with its Securities and Exchange Commission (“SEC”) reporting requirements. The Company ended the deferral of release in February 2019. The deferral of release and its removal were both modifications to the Awards; however, the impact of the modifications were not material and no incremental compensation expense was recorded. All employees with outstanding stock-based awards were impacted by the modifications.

Quantum has an employee stock purchase plan (the “Purchase Plan”) that allows participating employees to purchase shares of the Company’s common stock at a discount to fair market value. Employees may purchase the Company’s common stock at a price that is no less than the lower of 85% of the fair market value at the grant date or exercise date. The maximum number of shares that may be issued under the Purchase Plan is 8.9 million shares. The Purchase Plan is available to all employees subject to certain eligibility requirements. Under the Purchase Plan, rights to purchase shares are granted during the second and fourth quarter of each fiscal year. The Purchase Plan allows a maximum amount of 0.3 million shares to be purchased in any to one year offering period. Employees did not purchase any shares of common stock under the Purchase Plan during the three-month periods ended June 30, 2019 and 2018, respectively.

The Company granted 175,000 and 125,000 performance share units with market conditions (market “PSUs”) during the three-month periods ended June 30, 2019 and 2018, respectively. The number of PSUs issued is dependent on Quantum’s common stock achieving certain average closing stock price targets as of specified dates and the Company becoming current with SEC reporting requirements or the Company becoming current with SEC reporting requirements and being relisted on a national stock exchange. PSUs issued vest one to three years after the issuance date based on the stock price targets achieved. The estimated fair value of these PSUs is determined at the issuance date using a Monte Carlo simulation model.