Introduction
Restricted stock units (RSUs) are a common form of employee compensation in the United States, particularly among technology companies, startups, and publicly traded businesses. They allow employees to receive company shares after meeting specific vesting requirements.
Although RSUs can increase your total compensation, their tax treatment often creates confusion. Many employees assume that the taxes withheld when their RSUs vest represent the full amount they owe. In reality, RSU tax withholding is a prepayment toward your tax liability, not necessarily your final tax bill.
Your actual tax depends on several factors, including your total annual income, filing status, deductions, tax credits, state of residence, and other compensation. If your employer withholds less than your final tax liability requires, you may owe additional money when filing your federal income tax return. If too much is withheld, you may receive a refund, assuming your overall tax payments exceed your liability.
Understanding the difference between withholding and actual tax can help you budget for vesting events, avoid unexpected tax bills, and make informed decisions about your equity compensation.
This guide explains how RSU taxation works under US federal tax rules, why withholding can differ from actual tax, and what you can do to plan ahead.
What Is RSU Tax Withholding?
RSU tax withholding is the amount your employer collects or remits toward applicable taxes when restricted stock units are settled as compensation, typically when they vest under the award’s terms.
Unlike a cash bonus that arrives entirely in your paycheck, RSUs may be settled through shares, with some shares withheld or sold to cover taxes. The precise process depends on your employer’s equity plan and payroll arrangements.
For federal income tax purposes, the fair market value of RSUs generally becomes ordinary wage income when the shares are transferred to you after vesting. The income is generally subject to applicable employment taxes as well.
For example, suppose you receive 100 RSUs that vest when the company’s stock price is $150 per share.
Your taxable wage income from the vesting event would generally be:
100 shares × $150 = $15,000.
That $15,000 is included in your wage income, even if your employer delivers only part of the shares to your brokerage account after withholding taxes.
The amount withheld is credited toward your tax payments. It does not automatically establish how much tax you ultimately owe on the RSU income.
For additional information, review the IRS guidance on supplemental wages and its rules for federal tax withholding.
What Is Actual Tax on RSUs?
Actual tax is the tax liability calculated under the applicable tax laws after considering your complete financial situation for the year. For federal income tax, this calculation includes your RSU income alongside salary, bonuses, investment income, deductions, and eligible tax credits.
Your RSUs generally do not receive a separate, standalone federal income tax rate simply because they are stock compensation. Their vesting value is generally treated as ordinary wage income and taxed under the applicable graduated federal income tax brackets.
Your actual tax can also include other applicable taxes, such as Social Security, Medicare, and state or local income taxes.
Three factors are especially important:
- Total annual income: Your salary, bonuses, and RSU vesting income all contribute to your overall income.
- Marginal tax bracket: Additional RSU income may fall partly or entirely within a higher federal tax bracket.
- Other tax considerations: Filing status, deductions, credits, state taxes, and payroll tax limits can affect your final liability.
The IRS explains the federal income tax brackets and withholding rules in its official publications. See IRS Publication 15 for employer withholding requirements and supplemental wage rules.
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RSU Tax Withholding vs Actual Tax: Key Differences
Although both figures relate to taxes on your compensation, they serve different purposes.
| Feature | RSU tax withholding | Actual tax |
| Purpose | Pays tax during the year | Determines your final tax liability |
| Calculation | Uses applicable payroll withholding methods | Uses your complete annual tax situation |
| Timing | Usually occurs when RSUs vest and settle | Determined through annual tax calculations |
| Income considered | Depends on the withholding method and payroll circumstances | Includes all relevant taxable income |
| Result | May be too high or too low | Establishes the amount actually owed |
| Tax return effect | Counts toward payments already made | Compared with payments and credits to determine the balance or refund |
The central distinction is that withholding is a payment mechanism, while actual tax is the final calculation.
For this reason, a person can have substantial tax withheld from RSUs and still owe money when filing a return.
Why Is RSU Tax Withholding Often Too Low?
One of the most common reasons employees face an unexpected tax bill is that federal income tax withholding on RSUs may not match their marginal federal income tax rate.
1. The 22% Federal Supplemental Wage Withholding Rate
For 2026, employers may generally use a flat 22% federal income tax withholding rate on qualifying separately identified supplemental wages when the applicable conditions are met. Supplemental wages exceeding $1 million from an employer during the calendar year are generally subject to mandatory 37% withholding on the excess.
These are withholding rules, not special final tax rates for RSUs. Employers may also use other permitted withholding methods when the applicable conditions allow them.
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Consider an employee whose marginal federal income tax rate is 32%. If $50,000 in RSU income is subject to 22% flat federal withholding, the withholding would be:
$50,000 × 22% = $11,000.
If the employee’s marginal federal income tax rate on that additional income is 32%, the simplified marginal-tax estimate would be:
$50,000 × 32% = $16,000.
The difference is $5,000.
This is an illustration, not a calculation of the employee’s complete tax liability. The actual result depends on taxable income, filing status, deductions, credits, and other factors.
The example shows why RSU withholding can fall short when the employee’s marginal tax rate is higher than the withholding rate.
2. RSUs Increase Your Total Annual Income
Your employer may calculate withholding on RSU income separately from your regular salary. However, your final federal income tax calculation considers the combined effect of your taxable income.
Suppose your annual salary is $160,000 and your RSUs add another $40,000 in vesting income. Your total wage income becomes $200,000 before considering other income, deductions, or adjustments.
The additional RSU income may push some of your taxable income into a higher marginal bracket. The actual effect depends on your filing status and taxable income rather than gross wages alone.
3. Multiple Vesting Events Can Add Up
Employees often receive RSUs quarterly, semiannually, or according to another vesting schedule.
Each vesting event can generate additional wage income. Even if withholding appears reasonable for an individual event, the cumulative effect of multiple events may create a shortfall.
Review your year-to-date vesting income and tax withholding instead of assessing each vesting event in isolation.
4. State and Local Taxes May Also Apply
Federal withholding is only one part of your potential tax obligation.
Depending on where you live and work, state and local income taxes may apply to RSU compensation. State rules can differ, especially when you move between states or work in multiple locations during the vesting period.
Review your payroll statement and consult the relevant state tax authority if your circumstances involve more than one state.
5. Payroll Taxes Are Different From Federal Income Tax
RSU compensation may also be subject to Social Security and Medicare taxes.
For 2026, the employee Social Security tax rate is generally 6.2%, up to the applicable Social Security wage base of $184,500. The employee Medicare tax rate is generally 1.45%, without a wage base limit. An additional 0.9% Medicare tax may apply to wages above the applicable threshold.
These taxes have rules and thresholds that differ from federal income tax withholding. As a result, the total amount withheld from your RSUs may include several different tax components.
See the IRS 2026 Employer’s Tax Guide for current payroll tax rules.
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How RSU Tax Withholding Works: A Practical Example
Consider a hypothetical US employee with the following RSU vesting event:
Illustrative RSU vesting example
Number of vested shares
200
Stock price at vesting
$100
Total vesting value
$20,000
Illustrative federal income tax withholding at 22%
$4,400
The example excludes Social Security, Medicare, state taxes, and any other withholding.
The $20,000 vesting value is generally included in ordinary wage income. The $4,400 is a federal income tax prepayment, not a final assessment of the tax owed on the shares.
If the employee’s actual federal tax attributable to the additional income were higher than $4,400, the employee could owe more at filing. If the employee’s overall tax payments exceed their final liability, they could instead receive a refund.
Importantly, the actual tax attributable to the RSUs cannot always be calculated by multiplying the vesting value by one tax rate. The correct calculation depends on the employee’s complete annual tax situation.
What Happens When You Sell RSU Shares?
Understanding the difference between vesting and selling is essential for avoiding double taxation.
RSUs can create two separate tax events.
Event 1: Tax at Vesting
When RSUs vest and are transferred to you, their fair market value is generally treated as ordinary wage income.
For example, if 100 shares vest at $100 per share, the vesting value is $10,000. That amount generally becomes wage income.
Event 2: Capital Gain or Loss When You Sell
After the shares are transferred to you, a later sale can create a capital gain or loss.
Your cost basis is generally the amount already included in income at vesting, subject to the applicable tax rules and any necessary basis adjustments.
Suppose your 100 shares have a $100-per-share basis at vesting:
- Cost basis: $10,000.
- Sale value at $120 per share: $12,000.
- Capital gain: $2,000 before applicable transaction costs or adjustments.
The $2,000 gain is generally a capital gain rather than additional ordinary wage income. Its tax treatment depends on how long you held the shares and your individual circumstances.
If you sell the shares at $90 each, the sale would instead produce a $1,000 capital loss before applicable adjustments.
The holding period generally begins when the shares are transferred to you, not when the RSUs were originally granted. Review IRS Publication 550: Investment Income and Expenses for more information about investment gains, losses, and cost basis.
Important: Check your brokerage Form 1099-B and your employer’s Form W-2 carefully. In some cases, the reported basis on Form 1099-B may not reflect the full amount previously included in wages. An incorrect basis can lead to reporting errors and potentially paying tax twice on the same economic value.
How to Avoid an RSU Tax Bill at Filing
You cannot determine your final tax bill from the withholding rate alone. However, you can take practical steps to reduce the risk of an unexpected balance due.
1. Estimate Your Full-Year Tax Liability
Include expected salary, bonuses, RSU vesting income, investment income, deductions, credits, and other relevant items.
Use the IRS Tax Withholding Estimator as a starting point, and consider professional assistance if your compensation includes substantial equity awards.
2. Review Your Pay Statements and Vesting Records
Track each vesting event, the number of shares vested, the value used for payroll, and the taxes withheld.
Compare these figures with year-to-date wages and withholding on your payroll statements. Keep your equity award statements and brokerage records for tax preparation.
3. Consider Additional Payroll Withholding
If your employer allows it, you may be able to increase federal income tax withholding from your regular paycheck by submitting an updated Form W-4.
This can help cover a potential shortfall without requiring a separate estimated tax payment. Your employer’s payroll department can explain the available options.
4. Evaluate Estimated Tax Payments
If your withholding is insufficient, you may need to make estimated tax payments using Form 1040-ES.
For 2026, the general federal safe-harbor rules typically require payments to reach the smaller of 90% of your expected current-year tax or 100% of the prior-year tax. The prior-year percentage generally increases to 110% for taxpayers whose prior-year adjusted gross income exceeded $150,000, or $75,000 for married taxpayers filing separately, subject to applicable rules and exceptions.
These thresholds are not a guarantee that you will owe nothing when filing; they generally address potential underpayment penalties. Your circumstances may require a different calculation.
Review IRS Publication 505: Tax Withholding and Estimated Tax for the relevant rules and payment deadlines.
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5. Review Your Situation After Major Vesting Events
A large vesting event, promotion, bonus, or change in employment can affect your annual tax estimate.
Revisit your calculations when your compensation changes materially instead of waiting until the end of the year.
How to Report RSUs on Your US Tax Return
Your employer generally reports RSU compensation as wages on Form W-2. The amount is typically included in Box 1, and applicable Social Security and Medicare wages are reported in the relevant boxes.
Federal income tax withheld is generally reported in Box 2. State and local wage and withholding information, where applicable, appears in other boxes.
When preparing your return:
- Check Form W-2 against your payroll and vesting records.
- Confirm that RSU wage income is included correctly.
- Review Form 1099-B for shares sold during the year.
- Verify the cost basis and report capital gains or losses as required.
- Include any estimated tax payments and other applicable tax payments.
If your employer uses a sell-to-cover arrangement, confirm how the shares sold or withheld for taxes were recorded. Do not assume that the net shares delivered to your brokerage account represent your full taxable compensation.
For official filing guidance, visit the IRS Form W-2 page and the IRS Form 8949 page.
Frequently Asked Questions
Why is my RSU tax withholding lower than my actual tax rate?
Your employer may use the permitted 22% federal supplemental wage withholding method, while your marginal federal income tax rate may be higher. Your final liability depends on your complete annual tax situation, not the withholding rate alone.
Are RSUs taxed twice in the United States?
Generally, the same vesting value is not taxed twice as ordinary income. The value at vesting is generally treated as wages, and a later sale creates a separate capital gain or loss based on the applicable cost basis. Incorrect basis reporting can cause apparent double taxation.
Can I owe taxes even if my employer withheld taxes from my RSUs?
Yes. Withholding is a prepayment. If your total tax liability exceeds your payments and credits, you may owe a balance when filing your return.
Is the 22% RSU withholding rate my final tax rate?
No. For 2026, 22% is an available federal supplemental wage withholding rate when the applicable requirements are met. It is not a special final tax rate for RSUs. Your actual federal tax may be higher or lower.
Should I sell my RSU shares to pay taxes?
That depends on your financial situation, investment risk tolerance, and goals. Selling shares can provide cash to cover taxes and reduce exposure to a single company, but it can also create a capital gain or loss. Consider the tax consequences and your overall investment strategy before deciding.
Do RSUs count as income for state taxes?
RSU compensation may be taxable at the state level. The applicable treatment depends on state law and your circumstances, including where you lived and worked during the relevant period.
Conclusion
Understanding RSU tax withholding vs actual tax is essential for managing equity compensation in the United States. Withholding helps pay taxes throughout the year, but it does not necessarily equal your final federal, state, or payroll tax liability.
The most effective approach is to track vesting income, review withholding, calculate your estimated annual tax, and account for capital gains or losses when shares are sold. If withholding appears insufficient, consider additional payroll withholding or estimated payments to help manage your obligations.
By reviewing these figures throughout the year, you can reduce the likelihood of an unexpected tax bill and make more informed decisions about your RSUs.
Disclaimer: This article is for general educational purposes and is not tax, legal, or investment advice. Federal and state tax rules can vary based on individual circumstances. Consult a qualified tax professional for advice about your specific RSU compensation and filing obligations.
