RSU Vesting Tax Guide 2026: Sell-to-Cover Explained

RSU Vesting Tax Guide 2026: How Sell-to-Cover, Withholding, and Capital Gains Actually Work

Restricted stock units can create a surprisingly large tax bill even when an employer automatically sells shares for taxes. The central issue is simple: RSUs are taxed as compensation when they vest, while sell-to-cover usually collects only the required withholding—not necessarily the full tax ultimately owed.

This 2026 RSU vesting tax guide explains the two taxable events, how shares are withheld or sold, why high earners may be underwithheld, and how to report the eventual stock sale without paying tax twice on the same income.

Important: This article provides general information for U.S. taxpayers with standard employee RSUs. It is not personalized tax, financial, or legal advice. Private-company awards, deferred settlement, multistate employment, and international assignments can require different treatment.

RSU Taxes at a Glance

Standard RSUs generally create two separate tax events:

1. Vesting: The fair market value of the shares delivered to you is generally treated as ordinary wage income.
2. Sale: Any change in value after vesting is generally treated as a capital gain or loss.

The stock’s fair market value on the vest date becomes your starting cost basis. That basis is essential because the vest-date value has already been included in compensation income.

Quick RSU tax example

Assume 2,000 shares vest when the stock trades at $100 per share:

• Shares vested: 2,000
• Vest-date price: $100
• Wage income: $200,000
• Starting cost basis: $100 per share, or $200,000 in total

The full $200,000 is generally compensation income even if some shares are immediately sold or withheld for taxes. If you later sell the remaining shares, only the price movement after vesting should create a capital gain or loss.

Sell-to-cover does not calculate your final tax liability. It is a mechanism for funding payroll withholding. Whether that withholding is sufficient depends on your total annual income, deductions, filing status, state residency, and other tax payments.

What Happens When RSUs Vest

When standard RSUs vest and shares are delivered, the employer generally includes their fair market value in your wages. The compensation typically appears on Form W-2 along with salary, bonuses, and other taxable pay.

The vesting income may be subject to:

• Federal income tax withholding
• State and local income tax withholding, where applicable
• Social Security tax, up to the annual wage base
• Medicare tax
• Additional Medicare Tax withholding after applicable wage thresholds

Federal supplemental wage withholding in 2026

Employers commonly treat RSU income as supplemental wages. When supplemental wages are separately identified, an employer may generally use the flat 22% federal withholding method while an employee’s annual supplemental wages remain at or below $1 million. The portion of supplemental wages exceeding $1 million is generally subject to mandatory 37% federal withholding.

An employer may use another permitted withholding method in some circumstances, so employees should review their pay statements and equity-plan documents instead of assuming every vest will be withheld at exactly 22%.

These percentages are withholding rates, not special RSU tax rates. RSU income is ultimately combined with other taxable income and assessed under the regular federal income tax rules.

AMT and 83(b) elections

Standard RSUs generally do not create the separate alternative minimum tax problem associated with exercising incentive stock options. The value is normally recognized as wage income when the award vests and settles.

Standard RSUs also usually do not qualify for an Internal Revenue Code Section 83(b) election. An 83(b) election generally requires property to be transferred subject to vesting restrictions. With a typical RSU, the employee receives an unsecured promise at grant rather than actual shares, so there is no stock transfer on which to make the election.

Sell-to-Cover: How the Share Math Works

Sell-to-cover means a broker automatically sells enough newly vested shares to fund the taxes the employer must withhold. The remaining shares are deposited into the employee’s brokerage account.

Example: 1,000 shares vesting at $100

Suppose 1,000 RSUs vest at $100 per share. The taxable compensation is $100,000. Assume payroll estimates that federal, state, and payroll withholding will total 35%:

• Total vest value: $100,000
• Estimated withholding: $35,000
• Approximate shares sold: 350
• Approximate shares delivered: 650

The exact result may differ because of stock-price movement, whole-share rounding, brokerage fees, local taxes, and payroll calculations. If 351 shares must be sold to cover a $35,000 obligation, any excess proceeds are typically reconciled through payroll or the brokerage process.

With combined federal, state, Social Security, and Medicare withholding, receiving roughly 600 to 700 shares from a 1,000-share vest is not unusual. A lower share count does not mean the company taxed only the shares you kept. The entire $100,000 vest value is generally wage income.

Sell-to-cover versus other withholding methods

Method	What happens	Practical result
Sell-to-cover	The broker sells enough vested shares to fund withholding.	You keep the remaining shares.
Net share withholding	The employer retains shares with a value equal to the withholding obligation.	Only the net number of shares is issued to you.
Same-day sale	All vested shares are sold immediately.	Taxes and costs are deducted, and you receive the remaining cash.
Cash payment	You provide cash for withholding.	You retain all vested shares but use other funds to pay the withholding.

Shares sold through sell-to-cover are still stock-sale transactions. They will usually appear on Form 1099-B. Because the sale occurs at or near vesting, the gain or loss is often small, but the transaction generally still needs to be reported.

Why RSU Withholding May Be Too Low

The 22% federal supplemental wage rate is a tax deposit. It is not a promise that 22% will cover the federal tax attributable to your RSU income.

Example: $400,000 salary plus $200,000 of RSUs

Consider an employee with $400,000 of salary and a $200,000 RSU vest, for $600,000 of total W-2 income before other compensation adjustments.

If the employer withholds 22% federally on the RSU income, the RSU-related federal withholding is $44,000. If much of the additional income falls in a 35% marginal bracket, the federal income tax associated with the vest could be closer to $70,000 before considering deductions and other return-level factors.

That simplified comparison suggests a potential $26,000 gap:

• Estimated tax at 35%: $70,000
• Federal withholding at 22%: $44,000
• Illustrative shortfall: $26,000

The actual shortfall cannot be calculated by looking at the vest alone. Regular paycheck withholding, deductions, credits, filing status, investment income, and prior payments all affect the final return.

Factors that can widen the gap

• Large bonuses in the same year
• Income from multiple employers
• A spouse’s earnings on a joint return
• Late-year vests that leave little time to adjust withholding
• Investment or business income without withholding
• Residency or workdays in a high-tax state or city
• Vesting in more than one state because of relocation or remote work

Social Security and Medicare considerations

For 2026, employee Social Security tax generally applies at 6.2% until wages reach the annual wage base of $184,500. Once an employee’s wages from the same employer exceed that limit, additional wages generally are not subject to further employee Social Security tax for that year.

Medicare tax generally applies at 1.45% without a wage cap. Employers must also withhold the 0.9% Additional Medicare Tax after wages paid to an employee exceed $200,000 during the calendar year.

The employee’s final Additional Medicare Tax threshold depends on filing status. It is generally $250,000 for married couples filing jointly, $200,000 for single and head-of-household filers, and $125,000 for married taxpayers filing separately. This can produce an adjustment when the tax return is filed.

Checklist for addressing possible underwithholding

• Project salary, bonuses, RSU income, and other taxable income for the full year.
• Compare projected taxable income with current federal and state tax brackets.
• Review year-to-date withholding after each major vest.
• Ask payroll whether a higher supplemental withholding election is available.
• Consider increasing regular paycheck withholding through Form W-4.
• Evaluate whether federal or state estimated tax payments are needed.
• Review underpayment safe-harbor rules with a qualified tax professional.

Selling Vested Shares: Cost Basis and Capital Gains

The grant-date value is generally not the basis for standard RSUs. Your starting basis is usually the fair market value recognized as wages when the shares vest and settle.

Example: Stock rises after vesting

Suppose 500 shares vest at $100 per share. You recognize $50,000 of wage income, and your starting basis is $50,000. If you later sell the shares at $120, the capital gain is generally $20 per share:

• Sale proceeds: $60,000
• Starting cost basis: $50,000
• Capital gain before transaction adjustments: $10,000

If you hold the shares for one year or less after acquiring them, the gain is generally short-term and taxed at ordinary federal income tax rates. If you hold them for more than one year, the gain is generally long-term and may qualify for preferential federal capital-gains rates.

A lower capital-gains rate does not necessarily make holding the stock the best decision. Waiting introduces company-specific risk, market risk, and the possibility that the shares will decline.

What if the stock falls?

If shares taxed at $100 are later sold at $80, the $20 decline is generally a capital loss. Capital losses can offset capital gains under applicable rules. If total capital losses exceed gains, an individual can generally deduct up to $3,000 of net capital loss against other income annually, with unused losses carried forward, subject to tax-law limitations.

The capital loss does not reverse the wage income recognized at vesting. A stock that falls from $100 to $80 after vesting can leave you with wage tax based on $100 and a separate capital loss based on the subsequent $20 decline.

Avoid double taxation

Some brokerage 1099-B statements report an incomplete or zero basis for RSU shares. If you report the full sale proceeds as gain, you may effectively pay tax twice on the value already included in your W-2.

Compare Form 1099-B with the vest confirmation and supplemental equity-compensation statement. When necessary, report the broker’s figure and make the appropriate basis adjustment on Form 8949 rather than silently substituting a different number.

Forms, Records, and Common RSU Mistakes

Keep the following records for every vesting lot:

• Form W-2: Reports wage income and payroll withholding.
• Vest confirmation: Shows the vest date, shares, fair market value, and withholding activity.
• Brokerage statements: Document shares sold for withholding and later sales.
• Form 1099-B: Reports stock-sale proceeds and may report cost basis.
• Form 8949 and Schedule D: Generally report and summarize capital gains, losses, and basis adjustments.

Common RSU tax errors

• Treating all stock-sale proceeds as capital gain
• Using the grant-date price instead of the vest-date value as basis
• Failing to report sell-to-cover transactions
• Assuming sell-to-cover settles the final tax bill
• Ignoring state or local tax obligations
• Combining multiple vesting lots with different dates and bases
• Using an unadjusted 1099-B basis that excludes compensation income

Wash-sale risks

A wash sale may occur when you sell stock at a loss and acquire substantially identical stock within 30 days before or after the sale. Recurring RSU vesting can create this issue if new company shares are delivered near a loss sale. Employee stock purchase plan acquisitions, dividend reinvestments, and purchases in another account may also matter.

The disallowed loss is generally added to the basis of replacement shares rather than disappearing permanently, but tracking can become difficult when several accounts or vesting lots are involved.

Foreign accounts and internationally mobile employees

Shares held through a foreign brokerage account may create additional reporting obligations. Depending on account values and other circumstances, U.S. taxpayers may need to consider the Foreign Bank Account Report, commonly called the FBAR, and Form 8938.

Employees who earned an RSU award while working in multiple countries may also need to allocate compensation among jurisdictions and evaluate foreign tax credits. International RSU taxation should be reviewed by a professional familiar with both U.S. and foreign rules.

What to Do Before Your Next Vest

1. Create a vesting calendar.

   Record each grant, expected vest date, share count, estimated stock price, and current withholding election. Include expected blackout periods if company trading rules may restrict sales.

2. Estimate the compensation income.

   Multiply expected shares by a reasonable stock-price range. Use multiple scenarios because the actual taxable amount depends on the vest-date fair market value.

3. Project total annual income.

   Add salary, bonuses, RSUs, investment income, and other compensation. Compare the result with applicable federal and state marginal tax brackets.

4. Review withholding options.

   Ask whether your employer permits a supplemental withholding rate above the default, offers net share withholding, or allows cash payment. Confirm deadlines for making an election.

5. Decide whether to hold or sell.

   After vesting, owning RSU shares is economically similar to using cash compensation to buy your employer’s stock. Consider concentration, liquidity needs, investment goals, and downside risk. Potential long-term capital-gains treatment should not be the only factor.

6. Save every confirmation.

   Retain vest statements, trade confirmations, payroll records, and supplemental basis reports. Organize records by vesting lot so basis and holding periods remain traceable.

The Bottom Line

RSUs are generally taxed first as wages at vesting and later as a capital gain or loss when the shares are sold. The vest-date value becomes the starting cost basis, while sell-to-cover simply funds required withholding.

The most important planning step is to compare the withholding collected at vesting with the tax rate likely to apply to your total annual income. Employees with large awards, high incomes, multiple state obligations, or international reporting issues should complete that review before the vest date and consult a qualified tax professional when the calculations become complex.