Your broker withholds 22% on RSU vests. Your real rate is higher.
Supplemental wages — RSU vests included — are federally withheld at a flat 22% unless your income crosses the annual $1,000,000 threshold, at which point the flat rate becomes 37%. Most engineers and operators sit below a million but well above the bracket where 22% is enough. This page estimates the gap.
Every salary-and-vest combination, computed: see the full 50-scenario index →
Where the vest lands your income
Marginal rate 24%
$1,875 until the 32% bracket
On each vest your broker withholds the flat supplemental rate of 22% . We compare that against the marginal federal income-tax rate the vest lands in, computed by stacking the vest value on top of your other income and walking the 2026 ordinary brackets.
The true rate is your marginal rate, not your average — RSU income is taxed at the rate of the last dollar it pushes you into. If you also owe the 3.8% net investment income tax it does not apply here: RSU income is compensation, not investment income, so §1411 is excluded from this estimate.
What you do about the gap is a W-4 question. Increasing withholding on remaining wages, or making an estimated payment, both close it. TaxGhost monitors the gap as it accumulates through the year.