S-Corp SEP-IRA Contributions: The W-2 Wage Limit Trap
If your S-corp funds a SEP-IRA, the contribution is capped at 25% of the W-2 wages your corporation actually paid you — not 25% of your net profit, and not a self-employment-tax-adjusted formula the way a sole proprietor’s SEP-IRA contribution would be calculated. For 2026, the dollar cap on top of that percentage is $72,000, and only the first $360,000 of compensation counts toward the 25% calculation. Mix up the wage-based S-corp rule with the self-employment rule used for sole proprietors and partners, and you’ll either contribute less than you’re allowed to or fund an excess contribution you have to unwind before the deadline.
Why an S-Corp SEP-IRA Works Differently Than a Sole Proprietor’s
A SEP-IRA contribution for any eligible employee is limited to the lesser of 25% of compensation or the annual dollar cap. The complexity is entirely in how “compensation” gets defined, and an S-corp shareholder-employee isn’t defined the same way a self-employed person is. The IRS’s own SEP guidance spells out a special computation that applies only to self-employed individuals — sole proprietors and partners — who must reduce their net self-employment earnings by one-half of self-employment tax and by the SEP contribution itself before applying the 25% rate, which nets out closer to 20% of gross earnings in practice.
None of that applies to you as an S-corp owner, because you aren’t self-employed for this purpose — you’re a W-2 employee of your own corporation. Your compensation for SEP calculations is the Box 1 wages your S-corp actually paid and reported, full stop. The K-1 income that passes through to your personal return is not compensation for SEP purposes, no matter how large it is. An owner who takes a modest reasonable salary and a large distribution can only base a SEP contribution on that salary — the distribution contributes nothing to the calculation, which is the opposite of how a lot of owners assume it works. We cover how that salary figure itself gets set in S-Corp Reasonable Salary: How to Set One (and Why the IRS Is Watching).
The 25% Limit and the $72,000 Cap for 2026
Under IRS guidance on SEP contribution limits, what an employer can contribute to any one employee’s SEP-IRA for 2026 cannot exceed the lesser of 25% of that employee’s compensation or $72,000, a figure tied to the Section 415(c)(1)(A) defined-contribution limit, set at $72,000 for 2026 by Notice 2025-67 and adjusted for inflation annually. That $72,000 ceiling only bites once compensation clears $288,000 — below that, 25% of wages is the binding number.
There’s also a ceiling on the compensation itself: for 2026, only the first $360,000 of an employee’s pay counts toward the 25% calculation. An owner paying themselves a $500,000 salary doesn’t get a bigger SEP contribution for the extra $140,000 — the math still runs on $360,000, capping the contribution at $72,000 either way once salary crosses that line. For an owner paying a $150,000 salary, the SEP math is simpler and the dollar cap never comes into play: 25% of $150,000 is $37,500, well under $72,000.
The Corporation’s Own 25% Deduction Ceiling
The per-employee contribution limit isn’t the only 25% rule in play. Under Internal Revenue Code Section 404(h)(1)(C), the amount an S-corp can deduct for SEP contributions in a tax year is separately capped at 25% of the total compensation paid, during that year, to the employees who are participants in the plan. If the corporation has several SEP-eligible employees and the combined contributions somehow exceed that aggregate 25% figure, the excess doesn’t disappear — it carries forward and becomes deductible in a later year, subject to that same 25% ceiling again. In a one-owner S-corp this limit almost never binds, since the per-employee 25% rule above already caps the same number, but it becomes the relevant constraint the moment there’s more than one SEP participant on the books.
The Nondiscrimination Rule That Trips Up Growing S-Corps
A SEP-IRA isn’t a plan you can run just for yourself once your S-corp has other employees. Under Section 408(k)(3)(C), employer contributions to a SEP are treated as discriminatory — and the plan loses its favorable treatment — unless contributions bear a uniform percentage relationship to compensation for every eligible employee. If you contribute 20% of your own salary to your SEP-IRA, you have to contribute 20% of compensation for every other eligible employee too, not a token percentage while you max out your own account.
Eligibility itself has its own floor: an employee generally has to be at least 21, have performed services in at least three of the preceding five years, and have received the SEP minimum compensation for the year (an inflation-adjusted figure, $800 for 2026) before they’re entitled to share in the uniform percentage. An owner who hired a part-time employee two years ago and forgot about the SEP entirely can find that employee already eligible — and already owed the same percentage the owner is taking.
When to Fund It, and Where the Deduction Lands
A SEP-IRA is one of the few retirement vehicles you can establish and fund after the year is already over. The corporation has until the due date of its Form 1120-S, including extensions, to both adopt the plan and make the contribution for that tax year — which for a calendar-year S-corp with a timely extension runs to September 15 of the following year. That flexibility is useful for a firm that doesn’t know its final numbers until well after December 31.
The deduction itself belongs to the corporation, taken on Form 1120-S, not to the shareholder’s Form 1040 — unlike a traditional or Roth IRA contribution, which an individual deducts (or doesn’t) on their own return. The contribution also never shows up in Box 1 of the shareholder-employee’s W-2; it’s excluded from wages entirely, with the employer only checking the “Retirement plan” box in Box 13. Get the mechanics backward — claiming the SEP contribution as a personal deduction, or running it through payroll as taxable wages — and the return overstates one side of the ledger and understates the other.
What This Means Before You Fund the Next Contribution
None of this makes a SEP-IRA the wrong choice for an S-corp — it’s still one of the cheapest, least administratively demanding ways to shelter income, with no Form 5500 filing and no annual compliance testing beyond the uniform-percentage rule. The real complexity shows up in the comparison nobody runs: a Solo 401(k) lets an owner-employee contribute an additional elective deferral on top of the same 25% employer contribution, which can produce a meaningfully larger total at the same salary level, especially below the $288,000 salary where the SEP’s dollar cap isn’t yet the binding constraint. We walk through how the related 401(k) rules apply to S-corp owners in S-Corporation 401(k): Are You Compliant Under SECURE 2.0?, and the How Much Should My S-Corp Pay Me? resource page covers the salary question that both plans ultimately depend on. If you’re deciding how much to contribute before this year’s extended deadline — or whether a SEP is still the right plan now that you’ve hired your first employee — talk to us before you fund it, not after.