Restricted stock units (RSUs) refer to an agreement by a company to issue an employee shares of stock or the cash value of shares of stock on a future date. Each unit represents one share of stock or the cash value of one share of stock that the employee will receive in the future. (They’re called units since they are neither stock nor stock options, but another thing altogether that is contractually linked to the value of stock.)
Definition The date on which an employee receives the shares or cash payment for RSUs is known as the settlement date.
RSUs are difficult in a startup or early stage company because when the RSUs vest, the value of the shares might be significant, and taxes will be owed on the receipt of the shares.* This is not a bad result when the company has sufficient capital to help the employee make the tax payments, or the company is a public company that has put in place a program for selling shares to pay the taxes. But for cash-strapped private startups, neither of these are possibilities. This is the reason most startups use stock options rather than RSUs or stock awards.
RSUs are often considered less preferable to grantees since they remove control over when you owe tax. Options, if granted with an exercise price equal to the fair market value of the stock, are not taxed until exercise, an event under the control of the optionee. If an employee is awarded an RSU or restricted stock award which vests over time, they will be taxed on the vesting schedule; they have been put on “autopilot” with respect to the timing of the tax event. If the shares are worth a lot on the date of vesting, the tax burden can be significant.