At these higher valuations, companies start to think about alternatives like RSUs (restricted stock units). With a restricted stock unit, the employee doesn't own any property. You just have the right to receive the value of a share of stock upon the occurrence of certain events. This results in income tax on the fair market value of the stock. This is particularly troubling for private company employees, since their ability to liquidate the stock to meet their tax burden is limited. Restricted stock is optimal when the company has little to no value and the recipient makes an 83(b) election. Otherwise, this instrument may result in huge tax burdens on the employee recipient.