An S-Corp owner in her fifties with a good year, a Solo 401(k) already full at $72,000, and a tax bill she would rather not pay has one lever left that most articles never mention: a defined benefit plan. Where a 401(k) caps what goes in, a defined benefit plan caps what comes out at retirement and works backward to a contribution, and for an owner with fifteen years to retirement that contribution is routinely $100,000 to $250,000 a year, all deductible to the company.
This guide explains how a defined benefit plan (usually set up as a cash balance plan) works for an S-Corp owner, why the salary decision matters even more here than for a 401(k), what the numbers look like at three ages, how it stacks with a 401(k), what it commits you to, and when it is the wrong tool.
A 401(k) or SEP is a defined contribution plan: the law limits what goes in each year ($72,000 in total additions for 2026) and the owner gets whatever that grows to. A defined benefit plan promises a benefit at retirement, up to an annual limit ($290,000 a year for 2026, based on the average of the owner's three highest years of compensation, itself capped at $360,000 for 2026), and an actuary computes what the company must contribute each year to fund that promise. The older the owner, the fewer years there are to fund the benefit, so the annual contribution is larger. That is the whole trick: a 55-year-old owner can put several times more into a defined benefit plan than into any defined contribution plan, because the plan is funding a promised pension rather than an annual allowance.
Contributions are made by the S-Corp and deducted by it, which for a pass-through means the deduction lands on the owner's K-1 and reduces the income taxed at the owner's marginal rate. The money grows tax-deferred and is taxed at withdrawal like any pre-tax retirement account; at retirement or plan termination it usually rolls into an IRA.
A traditional defined benefit plan expresses the benefit as a monthly pension for life, which is hard to explain and produces a contribution that swings with interest rates and investment returns. A cash balance plan is still a defined benefit plan in law, but it expresses the benefit as a hypothetical account: each year the plan credits a pay credit (a dollar amount or a percentage of salary set in the plan document) plus an interest credit at a stated rate. The owner sees a balance that looks like a 401(k), the contribution is more predictable, and the plan can set different pay credits for different classes of participants, which matters if the company has employees. For an owner-only S-Corp the choice is mostly about predictability, and cash balance wins.
Like every qualified plan in an S-Corp, the benefit and the contribution are computed from W-2 compensation, and distributions do not count. An owner who pays herself $60,000 to minimize payroll tax has a $60,000 benefit base, and the plan the actuary can build on that is small. To use a defined benefit plan properly, the salary usually has to rise, often well above the level chosen for payroll tax reasons, and the added payroll tax is the price of the deduction. The two decisions have to be modeled together; our guide to S-Corp salary vs distribution covers the compensation side, and the interaction is the reason the plan is worth doing for an owner clearing $250,000 and rarely for one clearing $120,000.
The contribution is set by the actuary from the owner's age, compensation, the plan's benefit formula and its interest assumptions, so the figures below are illustrative ranges rather than a quote. They assume a cash balance plan, a W-2 salary of $250,000, and a plan designed to reach a substantial fraction of the maximum benefit by 65.
| Owner's age | Years to 65 | Typical first-year cash balance contribution | Plus 401(k) deferral and 6% employer | Total sheltered |
|---|---|---|---|---|
| 45 | 20 | $90,000 to $130,000 | $24,500 + $15,000 | $130,000 to $170,000 |
| 52 | 13 | $150,000 to $200,000 | $32,500 (with catch-up) + $15,000 | $200,000 to $250,000 |
| 60 | 5 | $250,000 to $300,000+ | $35,750 (with the 60 to 63 catch-up) + $15,000 | $300,000 to $350,000 |
At $250,000 of salary and a 35% combined marginal rate, a $180,000 contribution is worth roughly $63,000 of tax deferred in the year. The number the owner should look at is not the deduction but the cash: the company has to have the $180,000, and next year, and the year after.
A defined benefit plan and a 401(k) can run side by side, and for owners they usually do. The owner keeps the full employee deferral ($24,500 for 2026, plus catch-ups). The employer's contribution to the 401(k) is limited to 6% of compensation when the company also sponsors a defined benefit plan that is not covered by the PBGC, which owner-only plans are not. At $250,000 of salary that is $15,000, so the combined package is the cash balance contribution plus roughly $40,000 to $50,000 through the 401(k). The plans have to be designed together, because the combined deduction limit and the coverage tests are computed across both.
A 401(k) contribution is optional every year. A defined benefit plan is a promise, and the law treats it that way. The plan has a minimum required contribution each year, set by the actuary; skipping it creates a funding deficiency with an excise tax. The IRS expects the plan to be permanent, which in practice means running it for at least three to five years before terminating it, and terminating early without a business reason invites disqualification of the deductions taken. The plan needs an enrolled actuary every year, a Form 5500 with the actuarial schedule, and a plan document that costs more than a 401(k)'s: typical fees for an owner-only cash balance plan run $2,000 to $5,000 a year, and setup is often similar. If the company has employees, the plan has to cover the eligible ones, and the controlled group rules aggregate every business the owner controls, so the fleet LLC's one W-2 driver or the spouse's practice can pull employees into a plan designed for the owner.
The adoption deadline is more generous than it used to be: since the SECURE Act, a company can adopt a defined benefit plan up to its tax filing deadline including extensions and have it count for the prior year, so an owner who discovers in February that last year was very good can still shelter part of it. The contribution itself has the same deadline. What cannot be done retroactively is the salary, which is why the compensation planning has to happen during the year.
It is the wrong tool when income is lumpy and next year's contribution is not certain; when the owner is under about 45, because the contribution is not much larger than a 401(k) and the commitment is; when the company's salary cannot be raised to a level that supports the plan; and when the owner has employees she is not prepared to fund benefits for. It is the right tool for an owner in her fifties or sixties with steady income above roughly $250,000, no employees or a small number she wants to cover anyway, and a plan to keep it running for at least five years.
The plan only works if the salary, the payroll, the contribution and the cash are visible together. HaraPro keeps the S-Corp's books, the owner's W-2, the plan contributions and the personal picture in one login, with the tax forecast updated as salary and contributions change, so the decision is modeled on the real numbers rather than on an actuary's illustration; the tax page shows the forecast, and our comparison of the Solo 401(k) and the SEP IRA covers the plans that come before this one.
Yes. The S-Corp sponsors the plan, contributes for the owner based on W-2 compensation, and deducts the contribution. Owner-only plans are common and are usually set up as cash balance plans.
The actuary sets the amount from age, salary and the plan's formula. Illustratively, at $250,000 of salary a 45-year-old might contribute $90,000 to $130,000 a year and a 60-year-old $250,000 or more, up to what is needed to fund a benefit of $290,000 a year (the 2026 limit).
Yes. You keep the full 401(k) employee deferral; the employer contribution to the 401(k) is limited to 6% of compensation when the company also sponsors a defined benefit plan not covered by the PBGC. The two plans must be designed together.
No. Only W-2 wages count, averaged over the three highest consecutive years. A low salary produces a small plan, which is why the salary decision and the plan decision are one decision.
The plan has a minimum required contribution set by the actuary; missing it creates a funding deficiency with an excise tax. Plans can be amended to reduce future accruals, and can be terminated with a business reason, but the IRS expects a plan to run for several years, so the plan is only appropriate for steady income.