Restricted Stock Units (RSUs)

RSUs are company shares granted to employees that convert to real stock on a vesting schedule. They're taxed as ordinary income at vesting on the full value, whether or not you sell — the single most common source of unexpected tax bills in tech, since default withholding of 22% often falls short of a high earner's actual rate. Holding after vesting is economically identical to buying your employer's stock with cash.