Retention Bonus Taxes: Withholding, FICA, and Repayment Rules

Retention bonus taxes work like any other bonus: the payment is treated as supplemental wages and taxed as ordinary income, with federal withholding usually set at a flat 22%, plus Social Security, Medicare, and state income tax. The catch is that 22% is a withholding rate, not your actual tax rate. If your salary already puts you in a higher bracket, the withholding will fall short of what you owe, and the difference lands on your return in April. A retention bonus tied to a merger or change in control carries a separate risk: a 20% federal excise tax on top of income tax if the payment crosses the golden parachute threshold.

How the IRS Treats the Payment

The IRS classifies a retention bonus as a supplemental wage, the same bucket that holds commissions, overtime, severance, and every other kind of bonus.¹ The classification is what drives the withholding math, and it’s why the tax bite on a lump-sum bonus can feel heavier than the same money spread across regular paychecks.

The gross amount shows up as wages on your Form W-2 for the year the money is paid.¹ The year of payment is the year of tax, regardless of when you signed the retention agreement or when the required service period began.

Federal Withholding: The Two Methods

Your employer chooses one of two ways to withhold federal income tax on the bonus. Both produce the same final tax bill when you file, but the take-home amount on payday can look very different depending on which one your payroll department uses.

Flat 22%

Most employers use the flat rate. They withhold 22% of the bonus for federal income tax and ignore your W-4 elections and filing status.¹ A $50,000 retention bonus loses $11,000 to federal withholding before it reaches your account.

A higher tier applies to very large payments. If your total supplemental wages from a single employer pass $1 million in a calendar year, every dollar above that mark is withheld at 37%, the top marginal rate.¹

Aggregate Method

The alternative is the aggregate method. The employer combines the bonus with your regular paycheck and runs withholding on the combined total as if it were a single payment for that pay period.² Because the payroll system treats that inflated amount as though it were your normal pay, the calculation temporarily pushes you into a higher bracket, and withholding on that single check can be substantially larger than 22%. The excess washes out when you file, but the net deposit can be a shock.

Why 22% Withholding Often Falls Short

The 22% flat rate is administrative shorthand, not a forecast of your actual liability. For 2026, the 22% bracket runs up to $105,700 in taxable income for single filers. Above that the rates climb to 24%, 32%, 35%, and 37%. If your regular salary already sits in the 24% or 32% bracket, a retention bonus withheld at 22% is under-withheld from the first dollar. On a $75,000 retention bonus for someone in the 32% bracket, that gap can run $7,500 or more.

Underpayment penalties are the second problem. The IRS charges a penalty when your total withholding and estimated payments fall short of a safe harbor: 90% of the current year’s tax or 100% of the prior year’s tax, whichever is smaller. If your prior-year adjusted gross income topped $150,000, the safe harbor rises to 110% of the prior year’s tax.³ A large retention bonus can leave you outside both safe harbors and owing a penalty on top of the balance due.

Social Security and Medicare

FICA applies to a retention bonus the same way it applies to regular wages. For 2026, Social Security tax runs 6.2% on earnings up to $184,500.⁴ If your salary already crosses the wage base before the bonus lands, no additional Social Security tax is due on the bonus. If it doesn’t, the bonus is taxed until your combined earnings reach the cap.⁵

Medicare has no cap. The 1.45% Medicare tax applies to every dollar of the bonus. An additional 0.9% Medicare surtax starts once your total wages for the year cross $200,000 for a single filer or $250,000 for a married couple filing jointly.⁶ Your employer begins withholding that extra 0.9% after year-to-date wages pass $200,000, regardless of your filing status. A bonus that carries you across that line triggers the surtax on the excess.

State Income Tax

Most states with an income tax also withhold on supplemental wages. Some apply a flat supplemental rate; others require employers to use the same progressive tables as regular wages. Supplemental rates range from roughly 1.5% to over 11% depending on the state. States with no income tax skip this layer entirely. If you live in one state and work in another, both may have a claim on the bonus, though most states offer credits to prevent full double taxation. The federal 22% withholding rate tells you nothing about what your state will take, so check your state’s rules directly.

Golden Parachute Risk If the Bonus Is Tied to a Merger

If your retention bonus is contingent on a change in corporate ownership or control, a separate set of federal tax rules can apply. When the total value of all change-in-control payments to a single individual reaches three times their average annual compensation over the preceding five years, the amount above one times that “base amount” is treated as an excess parachute payment.⁷

You owe a 20% excise tax on that excess, and it stacks on top of regular income tax.⁸ The employer also loses its deduction for the same excess.⁷ Federal and state income tax combined with the 20% excise can push the effective rate on the excess above 60%.

Two details are worth flagging. Any payment agreement signed within one year before a change in ownership is presumed to be contingent on that change unless the company shows otherwise with clear and convincing evidence.⁷ And the company can reduce or defeat the parachute classification by showing the bonus is reasonable compensation for services you’ll perform after the transaction closes. If you’re negotiating a retention package during M&A talks, the 280G analysis belongs in the conversation before you sign.

What Happens If You Have to Repay It

Retention agreements almost always include a clawback: if you leave before the vesting period ends, you owe the bonus back. The tax treatment of that repayment depends on when it happens.

Same Calendar Year

If you repay in the same year you received the bonus, the fix is clean. Your employer files a corrected payroll return (Form 941-X), reduces the reported wages, and adjusts the withholding.⁹ You should get a corrected W-2 reflecting the lower income. Your annual return then reflects only the money you actually kept.

A Later Tax Year

Repayment in a later year is harder. The income has already been reported, taxed, and filed. You can’t amend the prior return to remove it. When the repayment is more than $3,000, the tax code gives you two options:¹⁰

Deduct the repayment in the year you pay it back, reducing that year’s taxable income.
Calculate the tax decrease that would have resulted from excluding the bonus from the original year’s income, and claim that amount as a credit against the current year’s tax.

You use whichever produces a lower tax bill.¹¹ For repayments of $3,000 or less, the credit method isn’t available; you can only deduct in the repayment year. Where the original income was reported as wages, the deduction sits on Schedule A as an itemized deduction rather than a reduction of current wages.

FICA recovery is a separate track. Your employer has to file to recover the overpaid Social Security and Medicare tax, and getting your share back requires your written consent to the process. Without that consent, the employer can only recover its own half, and your portion is lost.⁹ Repaying the gross bonus while waiting on that refund can create a real cash squeeze.

When the Tax Actually Hits

A retention bonus is taxable in the year the money becomes available to you, not the year you signed the agreement. This tracks the constructive receipt doctrine: income counts when it’s credited to your account or set aside for you without substantial restrictions.¹²

For most retention bonuses, the requirement that you remain employed is a substantial restriction, so the tax clock doesn’t start until you satisfy it and the payment is made. Installments are taxed year by year as they’re paid. A lump-sum bonus at the end of a two-year period hits entirely in the year of payment.¹² A payment date on either side of December 31 can push the whole liability into a different tax year.

Using Your 401(k) to Cushion the Tax

Whether your retention bonus counts as eligible compensation for 401(k) deferrals depends on your plan document, not the tax code. The IRS treats bonuses as compensation that can be included, but each plan defines its own compensation formula, and some plans specifically exclude bonuses.¹³

If bonuses are eligible under your plan, a large payment is an opening. The 2026 employee deferral limit is $24,500, with an $8,000 catch-up for those 50 and older and an $11,250 catch-up for those aged 60 through 63.¹⁴ Routing part of the bonus into your 401(k) reduces the taxable income on that paycheck. You’ll pay tax on the money when you draw it in retirement, but the deferral can keep the bonus from tipping you into a higher current bracket. Most plans need you to change your deferral election before the bonus is processed, so talk to your plan administrator ahead of the payment date.

Steps to Take Before the Bonus Lands

A surprise April bill is the outcome to avoid. A few moves before payday do most of the work.

Run the bracket math. Add the gross bonus to your expected income and find your marginal rate. If you’re above 22%, the flat withholding won’t cover the liability.
Adjust your W-4. Step 4(c) lets you request additional withholding from each remaining paycheck, spreading the extra tax across pay periods instead of forcing an estimated payment later.¹⁵
Make an estimated payment. If the bonus arrives too late in the year to catch up through withholding, send an estimated payment directly to the IRS using Form 1040-ES.
Check your 401(k) plan. If bonuses are eligible compensation, raise your deferral percentage before the payment date.
Ask about 280G. If the bonus is connected to a merger or acquisition, find out whether a golden parachute analysis has been done. You want to know about the 20% excise before you sign, not after.
Read the clawback terms. Confirm whether you’d repay the gross or net amount if you leave early, and whether the agreement addresses the FICA recovery process.

The total tax burden on a retention bonus is no heavier than on any other cash compensation at the same income level. The pain comes from a large lump sum meeting a withholding rate that doesn’t match your actual bracket. Closing that gap before the money arrives is most of the job.

1
Internal Revenue Service. Publication 15 (2026), (Circular E), Employers Tax Guide
2
eCFR. 26 CFR 31.3402(g)-1 – Supplemental Wage Payments
3
Internal Revenue Service. Underpayment of Estimated Tax by Individuals Penalty
4
Internal Revenue Service. Topic No. 751, Social Security and Medicare Withholding Rates
5
Social Security Administration. Maximum Taxable Earnings
6
Social Security Administration. Social Security and Medicare Tax Rates
7
Office of the Law Revision Counsel. 26 US Code 280G – Golden Parachute Payments
8
Office of the Law Revision Counsel. 26 US Code 4999 – Golden Parachute Payments
9
Internal Revenue Service. Instructions for Form 941-X
10
Office of the Law Revision Counsel. 26 USC 1341 – Computation of Tax Where Taxpayer Restores Substantial Amount Held Under Claim of Right
11
Internal Revenue Service. 21.6.6 Specific Claims and Other Issues
12
eCFR. 26 CFR 1.451-2 – Constructive Receipt of Income
13
Internal Revenue Service. 401(k) Plan Fix-it Guide – You Didnt Use the Plan Definition of Compensation Correctly for All Deferrals and Allocations
14
Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500
15
Internal Revenue Service. Employees Withholding Certificate (Form W-4)