Restricted Stock Units (RSU's)
Restricted Stock Units (RSU's) are shares of company stock that are granted to employees as part of the overall compensation package. Once vested, the shares are owned by the employee and the fair market value of the shares on the vesting date is treated as ordinary income. As a result, the employee is subject to ordinary income taxes. Often, a portion of the shares will be withheld to cover the taxes and the rest will be the employee's to either sell or hold.
If you immediately sell your RSU's once they vest, it is essentially the equivalent to a cash bonus. If you choose to hold onto the shares for at least a year after they vest, any gains at the time of sale will be subject to long-term capital gains taxes. You will want to work with your tax professional to understand the specific tax implications at that time.