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How are FICA taxes calculated on stock compensation?

Social Security & Medicareadvanced3 answers · 6 min readUpdated February 28, 2026

Quick Answer

FICA taxes (7.65% employee + 7.65% employer) apply to stock compensation based on fair market value at vesting for RSUs, spread at exercise for options, and discount for ESPP. For 2026, Social Security tax stops at $176,100 of combined wages and stock income.

Best Answer

SC

Sarah Chen, Payroll Tax Analyst

Employees earning $150K+ who receive significant equity compensation and need to understand FICA implications on large vesting events

Top Answer

How FICA taxes work on different types of stock compensation


FICA taxes (Social Security 6.2% + Medicare 1.45% = 7.65% total for employees) apply to stock compensation based on the taxable income created when you receive or exercise the stock. The timing and calculation method varies significantly by compensation type.


RSUs (Restricted Stock Units): Taxed at vesting


RSUs are the most straightforward for FICA purposes. When your RSUs vest, the full fair market value becomes subject to FICA taxes immediately.


Example: You have 1,000 RSUs vesting when the stock price is $85 per share. The taxable income is $85,000, and you'll pay $6,502.50 in FICA taxes (7.65% × $85,000). Your employer pays the same amount.


Stock options: Taxed at exercise (for NQSOs)


For Non-Qualified Stock Options (NQSOs), FICA taxes apply to the "spread" — the difference between the exercise price and fair market value when you exercise.


Example: You exercise 2,000 options with a $20 strike price when the stock trades at $75. The spread is $55 per share × 2,000 = $110,000 in taxable income. FICA taxes: $8,415 (7.65% × $110,000).


*Note: Incentive Stock Options (ISOs) generally don't trigger FICA taxes at exercise, only when you sell the stock.*


ESPP (Employee Stock Purchase Plan): Taxed on the discount


ESPP creates FICA liability based on the discount you received, calculated when you purchase the shares.


Example: Your company offers a 15% discount on a $100 stock price. You buy 500 shares at $85 each. The $15 per share discount ($7,500 total) is subject to FICA taxes: $573.75.


The Social Security wage cap creates planning opportunities


For 2026, Social Security tax (6.2%) applies only to the first $176,100 of combined wages and stock compensation income. This creates strategic timing opportunities for high earners.



Additional Medicare Tax for high earners


Once your combined income (wages + stock compensation) exceeds $200,000 (single) or $250,000 (married filing jointly), you pay an additional 0.9% Medicare tax on the excess amount.


Example: $180,000 salary + $40,000 stock compensation = $220,000 total. Additional Medicare tax: 0.9% × ($220,000 - $200,000) = $180.


Key factors that affect your FICA liability


  • Timing of vesting/exercise: Large vesting events can push you over the Social Security wage cap
  • Multiple employers: Each employer withholds Social Security tax up to the cap, potentially causing overwithholding
  • Stock price volatility: Higher stock prices at vesting mean higher FICA taxes
  • Withholding elections: You can often elect additional federal withholding on stock compensation to cover the tax burden

  • What you should do


    1. Plan vesting timing: If possible, spread large vesting events across tax years to manage the overall tax impact

    2. Calculate total compensation: Add your salary and expected stock income to determine if you'll hit the Social Security wage cap

    3. Adjust withholding: Use supplemental withholding elections on stock compensation to avoid underpayment penalties

    4. Track multiple employers: If you change jobs, monitor total Social Security taxes withheld to claim any overpayment on your tax return


    Use our [paycheck calculator](tool:paycheck-calculator) to model how different stock compensation scenarios will affect your take-home pay and FICA liability.


    Key takeaway: FICA taxes on stock compensation are based on fair market value at vesting/exercise, with Social Security tax capping at $176,100 total income and Medicare tax applying to all compensation amounts in 2026.

    Key Takeaway: FICA taxes apply to stock compensation at fair market value when vested or exercised, with Social Security tax capping at $176,100 but Medicare tax applying to all amounts.

    FICA tax rates and wage caps for different compensation types in 2026

    Tax ComponentRateWage CapApplies To
    Social Security (employee)6.2%$176,100All compensation
    Social Security (employer)6.2%$176,100All compensation
    Medicare (employee)1.45%No capAll compensation
    Medicare (employer)1.45%No capAll compensation
    Additional Medicare0.9%No capIncome over $200K/$250K

    More Perspectives

    MR

    Marcus Rivera, Compensation & Benefits Analyst

    Employees who work multiple jobs and receive stock compensation, creating complex FICA withholding situations across employers

    Why multiple jobs complicate stock compensation FICA taxes


    When you have multiple employers and receive stock compensation from one or more of them, FICA tax withholding becomes more complex because each employer withholds taxes independently without knowing your other income sources.


    The Social Security overwithholding problem


    Each employer must withhold Social Security tax (6.2%) up to the wage cap ($176,100 for 2026) on their payments to you. This can result in overwithholding when your combined income exceeds the cap.


    Example: You earn $120,000 at Job A plus receive $80,000 in RSU income. You also earn $40,000 at Job B. Each employer withholds Social Security tax on their full payments:

  • Job A: 6.2% × $200,000 = $12,400 (but should cap at $120,000 salary portion)
  • Job B: 6.2% × $40,000 = $2,480
  • Total withheld: $14,880
  • Correct amount: 6.2% × $176,100 = $10,918
  • Overpayment: $3,962 (refundable on your tax return)

  • Medicare tax is always accurate


    Unlike Social Security tax, Medicare tax (1.45%) applies to all compensation with no wage cap, so multiple employers don't create overwithholding issues. The additional 0.9% Medicare tax on high earners may require estimated payments if withholding is insufficient.


    Tracking your total FICA exposure


    Create a spreadsheet to track:

  • Regular wages from each employer
  • Stock compensation income and vesting dates
  • FICA taxes withheld by each employer
  • Projected total income for the year

  • This helps you identify potential overwithholding and plan estimated tax payments if needed.


    Key takeaway: Multiple employers can cause Social Security tax overwithholding on stock compensation, but you'll get the excess refunded when you file your tax return.

    Key Takeaway: Multiple employers can cause Social Security tax overwithholding on stock compensation, but you'll get the excess refunded when you file your tax return.

    SC

    Sarah Chen, Payroll Tax Analyst

    Workers nearing retirement who may have accumulated significant stock compensation that vests around their retirement date

    Why stock compensation timing matters near retirement


    As you approach retirement, the timing of stock compensation can significantly impact your FICA taxes, especially if you're planning to reduce your regular income or have already exceeded the Social Security wage cap earlier in the year.


    Vesting after you stop working


    If your stock vests after you retire or reduce to part-time work, you'll still owe FICA taxes on the vesting value, but it may be your only significant income that year.


    Example: You retire in June 2026 after earning $100,000 in salary. In December, $150,000 worth of RSUs vest. Your total FICA liability:

  • Social Security: 6.2% × $176,100 (wage cap) = $10,918
  • Medicare: 1.45% × $250,000 (total income) = $3,625
  • Total: $14,543

  • This is higher than if the RSUs had vested while you were working full-time and already approaching the wage cap.


    Planning around Medicare enrollment


    Large stock compensation events can affect your Medicare Part B premiums through Income-Related Monthly Adjustment Amounts (IRMAA). The income that triggers higher premiums includes stock compensation at vesting.


    Consider accelerating or deferring vesting


    Some companies allow you to accelerate vesting before retirement or defer it afterward. The FICA implications should factor into this decision alongside income tax planning.


    Key takeaway: Stock compensation that vests near or after retirement still triggers full FICA taxes and can affect Medicare premium calculations, making timing strategies important.

    Key Takeaway: Stock compensation that vests near or after retirement still triggers full FICA taxes and can affect Medicare premium calculations, making timing strategies important.

    Sources

    fica taxesstock compensationrsustock optionspayroll tax

    Reviewed by Sarah Chen, Payroll Tax Analyst on February 28, 2026

    This content is for educational purposes only and is not a substitute for professional tax advice. Consult a qualified tax professional for advice specific to your situation.

    How Are FICA Taxes Calculated on Stock Compensation? | ExplainMyPaycheck