RSU tax withholding is a tax payment your employer makes when restricted stock units become taxable compensation. With sell-to-cover, a broker sells part of the award to fund that payment; you keep the remaining shares. Those sales cover payroll’s required withholding. Whether they cover your final bill depends on the rest of your household’s income and taxes.
When does RSU income become taxable?
For a typical public-company grant, shares are delivered when they vest. Their market value is then ordinary compensation income reported on your W-2. Granting the units usually creates no income tax.
Vesting and delivery can happen at different times, particularly for private-company or deferred-settlement awards. Check the grant’s settlement conditions before using its vesting date as the tax date.
Suppose 1,000 shares are delivered at $100 each. You recognize $100,000 of compensation even if some shares immediately go toward withholding. The shares generally have a $100-per-share tax basis: the amount already taxed as wages. A later sale creates a separate capital gain or loss based on the change from that value. The IRS equity-compensation guide explains the income and basis rules.
Which federal withholding rate applies?
Under the IRS supplemental-wage rules, eligible employers can use a flat 22% rate or an aggregate method that combines supplemental and regular wages. The 37% rate is mandatory on the portion of an employee’s annual supplemental wages exceeding $1 million, subject to the employer-aggregation rules. This is not a household-income threshold.
State and local income tax, Social Security, and Medicare can add to the amount withheld. The Social Security wage limit and Medicare rules apply separately.
Example: a federal withholding shortfall
Assume an $80,000 award is taxed entirely in the 35% federal bracket, and payroll uses 22% withholding:
| Item | Amount |
|---|---|
| Federal tax attributable to the award | $28,000 |
| Federal income tax withheld | $17,600 |
| Difference to fund | $10,400 |
This illustration excludes state tax, payroll tax, credits, and other changes to your return. If the income spans brackets, calculate each portion at its applicable rate. Withholding can be too low, too high, or close to the final amount.
Use the RSU withholding calculator to compare a stated federal rate with the withholding on a specific award.
How do companies collect the withholding?
| Method | What happens | What you keep |
|---|---|---|
| Sell-to-cover | A broker sells enough shares to fund withholding | The remaining shares |
| Net share withholding | The employer retains shares and remits the required payment | The remaining shares |
| Sell all | The broker sells the full award | Cash after withholding and fees |
| Cash payment | You fund withholding from cash, if the plan allows it | All delivered shares |
For example, if 1,000 shares settle at $100 and the combined required withholding is $30,000, a sell-to-cover transaction would sell 300 shares at that price and leave 700. This assumes no fees or price movement. You still received $100,000 of compensation; $30,000 was used to make tax payments.
Your plan determines which methods are available. A market sale can create a small gain or loss if its price differs from the compensation value. Net share withholding does not necessarily involve a brokerage sale. That distinction explains why two coworkers can receive similar net awards but different brokerage tax forms.
What should you check before the next award?
- Project the household’s full year. Include salary, bonuses, remaining awards, investment income, deductions, and a spouse’s income.
- Compare projected tax with payments. Count salary withholding and estimated payments, not just the award’s withholding.
- Fund a shortfall on time. Consider additional W-4 withholding or estimated payments. The IRS estimated-tax rules explain payment timing and penalty exceptions.
- Choose what to hold. Selling enough for withholding still leaves an investment decision about the remaining employer stock.
- Reconcile the records. Match the pay statement’s compensation and withholding to the award transaction detail. Then compare the broker’s reported sale proceeds and basis with the stock-plan supplement. Missing basis can cause wage income to be counted again as capital gain.
Nino’s AI software can help you work through your pay statements and financial questions in one place. If you want a human team to handle tax planning and filing, you can add Nino’s financial and tax services.