. the employee stock purchase plan allows eligible participants to purchase shares of the company 2019s common stock through payroll deductions of up to 20% ( 20 % ) of eligible compensation on an after-tax basis . plan participants cannot purchase more than $ 25000 of stock in any calendar year . the price an employee pays per share is 85% ( 85 % ) of the lower of the fair market value of the company 2019s stock on the close of the first trading day or last trading day of the purchase period