Companies do this so that their employees don't get into tax trouble. There were cases when the employees failed to sell the shares needed for taxes and later on the share price crashed and the employees were stuck with big tax bill. Like what I said in my other comment on options, the granted shares are regular income at market value; and if you don't sell enough and later have losses the losses would be capital loss. Unless you have other big gains to offset you can use only $3000 a year to offset your regular income.