Severance Tax Rate in California 2026: The 6.6% Rate, the 10.23% Trap, and the SDI Question

California’s 6.6% Supplemental Rate vs the 10.23% Bonus Rate: Which One Hits Severance?

California is one of the few states that assigns two different flat withholding rates to supplemental wages, and which one lands on a severance check is a question most laid-off employees never think to ask. The California Employer’s Guide (DE 44) and the EDD’s supplemental-wage information sheet set two rates: 10.23% for bonuses and stock options, and 6.6% for all other supplemental wages paid separately.

Severance sits in the second bucket. Under the EDD’s supplemental wage payments guidance (DE 231PS), a separately paid severance check is withheld for California personal income tax at the flat 6.6% rate — not the 10.23% rate that applies to a cash bonus or an equity vesting event. The distinction is real money. A payroll department that treats a severance lump sum as “a bonus” out of habit over-withholds state tax by 3.63 percentage points. On a $50,000 payout that is $1,815 of extra California withholding — recoverable at filing, but a genuine cash-flow hit during the months a person is job-hunting.

The federal layer sits on top and behaves the same in every state. Severance is supplemental wages under IRS Publication 15-A, withheld at a flat 22% on payments up to $1 million in a calendar year and 37% on the excess. So a California severance recipient sees combined income-tax withholding of 22% federal plus 6.6% state — 28.6% before payroll taxes. That is meaningfully below New York’s stacked state-plus-city load and well above the zero-state-tax floor of Texas severance.

Payment type	California flat PIT rate	Authority
Bonuses and stock options	10.23%	DE 44 / DE 231PS
Severance and other supplemental wages	6.6%	DE 231PS
Federal supplemental (all types)	22% (37% above $1M/year)	IRS Pub 15-A

Is Severance Subject to California SDI Withholding in 2026?

This is the highest-value question about California severance and the one with the murkiest public answer. Start with the rate: the California State Disability Insurance (SDI) employee contribution is 1.3% for 2026, with no taxable wage ceiling. Senate Bill 951 removed the wage cap effective January 1, 2024, so when SDI applies, it now applies to the first dollar and every dollar after it — there is no longer a point in the year where the deduction switches off.

The harder question is whether severance is covered wages for SDI at all. California’s answer is genuinely conditional, and the EDD spells it out in its Types of Payments information sheet (DE 231TP). For “Dismissal or Severance Pay,” the table marks the payment as subject to SDI under Section 926 of the California Unemployment Insurance Code — unless the conditions of Section 1265 of the CUIC are met.

Section 1265 is the provision California uses to treat true dismissal and severance payments as a form of supplemental unemployment compensation rather than wages for services. When a severance payment qualifies under CUIC Section 1265, it is not subject to SDI — the same statutory logic that keeps severance from reducing an unemployment check. A genuine lump-sum severance paid on involuntary termination generally clears this bar, which is why most severance recipients see no SDI line on the payment.

The exception is “wages in lieu of notice” — pay covering a specific notice period the employer chose not to have you work out. That payment is compensation for a period of employment, does not meet the Section 1265 conditions, and is subject to the 1.3% SDI deduction. The practical rule follows: how the separation agreement characterizes the money decides the SDI outcome. The label on the check is doing real tax work.

A useful check after the fact: California SDI withheld from a paycheck shows up as “CASDI” in Box 14 of the Form W-2. If a severance check that should have qualified under Section 1265 nonetheless carried a CASDI deduction, that is a signal the employer classified it as wages in lieu of notice — or classified it in error. The employer makes the Section 1265 call at the time of payment, so raising the characterization question before the check is cut is far easier than unwinding it afterward. Employment Training Tax and the UI contribution itself are employer-side taxes; they never appear as an employee deduction, so the only California payroll line an employee ever sees on severance is SDI, and only when Section 1265 does not apply.

Personal income tax is simpler and unconditional. The same DE 231TP table marks dismissal or severance pay as subject to PIT withholding under CUIC Section 13009(q) and reportable as PIT wages under Section 13009.5 — which is precisely why the 6.6% supplemental rate applies. Severance is always California-taxable income; only the SDI and unemployment treatments turn on the Section 1265 question.

A Worked Example: $35,000 Severance for a Los Angeles Tech Employee

Consider a Los Angeles software engineer earning $130,000 base salary, laid off in a 2026 reduction in force with a 14-week lump-sum severance of $35,000, paid as a separate check. Year-to-date wages have not crossed the Social Security base, and the payment qualifies as dismissal severance under Section 1265.

Withholding line	Rate	Amount
Federal supplemental income tax	22%	$7,700.00
California PIT (6.6% supplemental)	6.6%	$2,310.00
Social Security	6.2%	$2,170.00
Medicare	1.45%	$507.50
SDI (qualifies under Section 1265)	0%	$0.00
Total withheld		$12,687.50
Net to employee		$22,312.50

That is about 36.25% withheld. Now change one fact. Suppose the agreement labels the money “wages in lieu of 14 weeks’ notice.” SDI at 1.3% now applies — 1.3% × $35,000 = $455 — pushing the deduction to $13,142.50 and the effective withholding to roughly 37.5%. And if payroll had mistakenly applied the 10.23% bonus rate instead of 6.6%, California withholding would have been $3,580.50 rather than $2,310 — an extra $1,270.50 out of the check, recovered only when the state return is filed the following spring.

FICA follows federal rules regardless of California residence. Social Security is 6.2% up to the annual wage base ($176,100 for 2025, with a COLA adjustment for 2026 per the Social Security Administration); Medicare is 1.45% on all wages, plus a 0.9% surcharge once year-to-date wages cross $200,000. A senior engineer separated late in the year may already have exceeded the Social Security base on prior wages, dropping the 6.2% line from the severance entirely and lowering the effective rate further.

Why California Severance Doesn’t Reduce Your Unemployment Check

Here California diverges sharply from New York. In California, severance pay does not reduce or delay unemployment insurance benefits. The EDD’s benefit-determination guidance, Total and Partial Unemployment (TPU 460.35), rests on the California Supreme Court’s 1965 decision in Powell and Byrd v. California Unemployment Insurance Appeals Board, which held that dismissal and severance payments “were not wages but were a form of supplemental unemployment compensation benefits.”

The practical consequence is direct: a laid-off Californian can collect the full weekly unemployment benefit and the full severance at the same time, with no offset and no waiting penalty tied to the severance. This is the mirror image of the wages-in-lieu-of-notice trap — the same Section 1265 logic that exempts true severance from SDI also protects the unemployment benefit. File for unemployment the week of separation regardless of the severance schedule, because waiting gains nothing.

One caveat is worth flagging. “Wages in lieu of notice” can be treated as disqualifying for the specific period it covers, because it is not severance in the Section 1265 sense. That is the second reason the characterization of the payment matters so much: a single phrase in the agreement drives the SDI deduction and the unemployment timing at once.

How the 6.6% Withholding Reconciles Against California’s 13.3% Top Bracket

The 6.6% state rate is a withholding rate, not a final tax rate — and in California the reconciliation gap usually runs the opposite direction from New York. California’s brackets climb from 1% to 12.3%, with an additional 1% Mental Health Services surcharge on taxable income above $1 million, for a 13.3% top marginal rate. For most white-collar severance recipients, the marginal California rate lands between 8% and 9.3%, comfortably above the flat 6.6% supplemental rate.

That means the 6.6% withholding typically under-withholds California tax. A recipient whose severance stacks on a full year of six-figure salary should expect to owe additional state tax at filing on the severance portion — the opposite of the modest state refund a New York recipient often sees, and a genuine contrast with the reconciliation math in most higher-withholding states. The exact balance depends on the year’s total income, deductions, and credits; withholding alone does not tell you the answer, and a large severance in a high-income year can produce a four-figure California balance due.

Because the 6.6% rate under-withholds for most earners, California’s estimated-tax rules deserve a glance. The Franchise Tax Board can assess an underpayment penalty when too little tax is paid in during the year, and a large severance withheld at only 6.6% can open exactly that gap for a high earner. Making a voluntary estimated payment in the quarter the severance lands — rather than waiting for the April true-up — is the standard way to close it. This is another point where California severance behaves unlike a New York package, where the higher state withholding usually leaves the taxpayer paid-ahead rather than behind.

Federal reconciliation works as it does everywhere. The 22% supplemental rate sits between brackets: for a filer whose top dollars land in the 24%, 32%, or 35% bracket, the 22% withholding under-withholds and a balance is due; for a lower earner in the 12% bracket, it over-withholds and refunds. IRS Publication 525 governs the year-end true-up on both the federal and — indirectly, through adjusted gross income — the state return. Anyone modeling the take-home number can run the figures through an after-tax severance calculator at SeveranceCalc.com and compare the result against the withholding actually applied on the pay stub.

What’s Worth Confirming Before Signing a California Separation Agreement

Three checks materially change the after-tax outcome on a California severance, and all three are settled before signing:

1. Is the payment labeled “severance” or “dismissal pay,” or is it “wages in lieu of notice”? The first qualifies under Section 1265 — no SDI deduction and no unemployment offset. The second is subject to 1.3% SDI and can disqualify unemployment for the period it covers. The language is negotiable at signing.

2. Did payroll apply 6.6% or 10.23%? Severance takes the 6.6% supplemental rate; the 10.23% rate is for bonuses and stock options. A wrongly applied bonus rate over-withholds by 3.63 points and only reconciles at filing.

3. Will total income for the year cross $1 million? The 37% federal supplemental rate on the excess over $1 million per calendar year is material for senior executives, and splitting a payment across two tax years is sometimes negotiable.

None of these change the formulaic severance amount, but each moves the after-tax take-home — sometimes by thousands of dollars. Because the 6.6% state rate under-withholds against most Californians’ marginal rate, budgeting for a state balance due at filing is the prudent default rather than the exception. Consider consulting a CPA or tax attorney for advice specific to your situation, particularly where the payment straddles two tax years or blends severance with wages in lieu of notice. Tax law changes annually; this article reflects 2026 rates and is refreshed each January.