Severance Withheld at 22% Flat: When You Owe $14K More

Marcus is a single filer in Austin, Texas. He earned $200,000 in base salary through October, then got laid off with a $150,000 severance lump sum. His pay stub for the severance shows $33,000 of federal income tax withheld — exactly 22%. He assumes that’s his tax bill handled. It is not. Marcus is already in the 32% federal bracket, and that 22% flat withholding will leave him owing roughly $14,000 more when he files — plus a possible underpayment penalty. Here is why, and how a single estimated payment fixes it.

Why your severance was withheld at exactly 22%

Severance is a supplemental wage in the eyes of the IRS — the same category as bonuses, commissions, and accumulated PTO payouts. Supplemental wages are not withheld using your W-4 and the regular wage tables. They have their own rule.

Under IRS Pub. 15 (Circular E), §7, and IRC §3402, when supplemental wages are paid separately from regular wages, the employer applies a flat 22% federal withholding rate on amounts up to $1 million per recipient per year. The portion of supplemental wages above $1 million is withheld at a mandatory 37% — the top federal rate. No W-4 allowances, no adjustment for your actual income, no judgment call. The payroll system simply multiplies your severance by 22% and remits it.

That 22% is a withholding rate. It is the IRS’s rough-cut estimate of what an average recipient owes. It is not your tax rate. Your actual federal tax is computed at filing on the §1 brackets, against your full year of income. For anyone whose income stays inside the 22% bracket, the flat withholding happens to line up. For higher earners, it under-collects — and the IRS comes back for the difference in April.

The 2026 brackets that decide whether you owe

The 22% withholding rate matches the 22% income-tax bracket. That bracket tops out at $103,350 of taxable income for a single filer and $206,700 for married-filing-jointly in 2026. The moment your total income climbs into the 24% bracket or higher, the flat 22% withholding falls short of your real marginal rate.

The principle is simple: your severance is not taxed in a vacuum. It stacks on top of your other income and is taxed at your highest marginal rates. If your salary already fills the lower brackets, the severance lands in the 32% bracket (or higher) — while only 22% was withheld.

Marcus’s math: where the $14,000 comes from

Walk through Marcus’s full year. Single filer, Texas (no state income tax), 2026 standard deduction of $15,750.

Without the severance, Marcus’s $200,000 salary leaves taxable income of $184,250 — topping out in the 24% bracket. The $150,000 severance stacks on top, so the first slice (up to $197,300 taxable) is taxed at 24%, then the bulk lands in the 32% bracket ($197,301–$250,525), and the top slice spills into the 35% bracket (above $250,526). Blended, the severance is taxed at roughly 31–32% federally — about $47,000. His employer withheld only $33,000. The difference, near $14,000, is a balance due.

Note one thing Texas residents get for free: no state income tax. A Marcus in California would also owe state tax (severance withheld at only 6.6% per FTB DE 44, against a marginal state rate that can reach 9.3% or higher) — a second shortfall stacked on the federal one.

The underpayment penalty most people don’t see coming

A $14,000 balance due is bad enough. The IRS may add an underpayment penalty on top, under IRC §6654. The penalty applies when you have not paid in enough tax throughout the year — through withholding and estimated payments combined — to hit a safe harbor.

There are two safe harbors. You avoid the penalty if your total tax paid in during the year is at least:

• 90% of the current year’s total tax, OR
• 100% of last year’s total tax — bumped to 110% if your prior-year adjusted gross income exceeded $150,000.

Marcus’s prior-year AGI was around $190,000, so his safe harbor is 110% of last year’s tax. The 22% flat withholding on a six-figure severance plus normal salary withholding may or may not clear that bar — and if it doesn’t, the penalty is charged quarter by quarter at the IRS underpayment rate (a moving figure tied to the federal short-term rate plus 3 points, recently in the 7–8% annualized range). The penalty is not catastrophic, but it is avoidable, and that is the point.

The fix: one estimated payment, the right quarter

The clean solution is a Form 1040-ES estimated tax payment made in the same quarter you receive the severance. Estimating the gap takes one line of arithmetic:

1. Find your top marginal rate on the severance using the bracket table above (for Marcus, blended ~32%).
2. Subtract the 22% already withheld. For Marcus: 32% − 22% = a 10-point gap.
3. Multiply by the severance. 10% × $150,000 = roughly $15,000 — close to his actual $14,000 shortfall after the 24%-bracket slice is accounted for.
4. Add any NIIT exposure. If the severance pushes your MAGI over $200,000 (single) or $250,000 (MFJ), a 3.8% Net Investment Income Tax (IRC §1411) hits your investment income — not the wages themselves, but the surcharge can apply to dividends and capital gains now sitting above the threshold.
5. Pay it by the quarterly deadline. Q1 (Apr 15), Q2 (Jun 15), Q3 (Sep 15), Q4 (Jan 15). Marcus got his severance in October, so his Q4 payment is due January 15.

Why withholding beats a lump estimated payment in one specific case: withholding is treated as paid evenly across the year for penalty purposes, while an estimated payment counts only from the date you make it. If you can still adjust withholding before year-end — for example, by submitting a new Form W-4 with an extra amount on Line 4(c) for any remaining paychecks, or by asking the employer to withhold extra on a later supplemental payment — that can retroactively cure earlier under-withholding. If not, the targeted 1040-ES payment in the correct quarter is the next-best lever.

What most people get wrong about that 22%

Three myths show up over and over in layoff forums and on pay-stub questions:

• Myth: “22% is the tax on severance, so I’m done.” No. 22% is a withholding default under Pub. 15, §7 — the IRS’s stand-in rate. Your real tax is computed at filing on your full-year income. If you’re a high earner, 22% is too little.
• Myth: “Severance is taxed at a special, lower rate.” No. Severance is ordinary wage income. It is also subject to FICA — Social Security tax up to the $181,800 wage base in 2026, plus 1.45% Medicare with no cap, plus the 0.9% Additional Medicare Tax on wages over $200,000. There is no preferential rate for being laid off.
• Myth: “I’ll just get a smaller refund.” For most middle earners, under-withholding means a smaller refund — annoying but harmless. For a high earner with a large severance, it means a five-figure balance due, with cash that may already be spent and a penalty attached. Different problem entirely.

There is one upside worth naming: if the severance is your last income of the year and you have no other earnings — say you were laid off in January and won’t work again until next year — the 22% flat rate may actually over-withhold, and you’ll get a refund. The flat rate cuts both ways. The trap is specifically for people whose other income already fills the lower brackets.

Severance over $1 million: the 37% layer

If your total supplemental wages for the year exceed $1 million, the rules change at the threshold. Under IRS Pub. 15, §7, the first $1 million of supplemental wages is withheld at the flat 22%, but every dollar above $1 million is withheld at a mandatory 37% — the top federal rate, with no employer discretion. For a $1.5 million package, that means $1,000,000 withheld at 22% ($220,000) and $500,000 at 37% ($185,000). At that income level the 37% mandatory rate is much closer to the actual liability, so the April surprise is smaller — but it’s still worth modeling state withholding and NIIT separately.

Your decision lever

The number that matters is the gap between your top marginal bracket and the 22% that was withheld. Multiply that gap by your severance, add NIIT if your investment income now sits above the threshold, and make a 1040-ES payment in the quarter you received the check. For Marcus, that is one ~$14,000 payment due January 15 — the difference between a clean filing and a five-figure balance plus a §6654 penalty. Do the subtraction the day the severance hits your account, not the day you open TurboTax in April.