How some owners can deduct six figures in one year
Defined benefit and cash balance plans, explained without the jargon — how they can let some owners deduct far more than a 401(k), and why the set-up date matters as much as the size.
Key takeaways
- A defined benefit or cash balance plan is funded toward a target benefit, so the deduction can be several times a 401(k)’s.
- Age and income drive the number; only an actuarial feasibility study can size it.
- Ideally set it up by December 31 and fund it by your filing deadline — earlier leaves more room to design.
- It is a multi-year commitment and a tax deferral, so steady cash flow matters more than year one.
The short answer
Some profitable owners can deduct six figures in one year by adding a defined benefit or cash balance plan on top of a 401(k). Because the plan is funded toward a target retirement benefit, not a fixed cap, older, high-income owners can often contribute several times the 401(k) limit. Timing is the catch: ideally set it up by December 31 and fund it by your filing deadline.
When to act
September–November
Run the feasibility study and check the cash flow while every design option is still open.
Before the final payroll
S corporation owners: set W-2 salary with the plan in mind — distributions generally don’t count toward the benefit.
By December 31
Ideally sign the plan document for the year you want the deduction.
By your filing deadline
Fund the contribution — generally by the tax-filing deadline, including extensions, often up to 8.5 months after year-end.
Why a 401(k) runs out of room
A 401(k) with profit sharing is a defined contribution plan. The IRS caps what can go in each year, and a profitable owner reaches that cap quickly. After that, every additional dollar of profit is taxed at your top marginal rate.
A defined benefit plan works the other way round. It starts with a retirement benefit — a target the plan promises to pay — and works backward to what must be contributed each year to fund it. The IRS limits the benefit, not the annual contribution. An actuary calculates the contribution, and for the right owner it can be several times what a 401(k) allows.
A cash balance plan is a type of defined benefit plan. Instead of a monthly pension, it expresses the benefit as a hypothetical account balance that grows by a set credit each year. It is easier to explain, more flexible to design, and it can sit alongside an existing 401(k).
Why age and income drive the number
Two inputs do most of the work. The first is income: the benefit a plan can target is tied to your compensation, so higher, steady earnings support a larger benefit. The second is age: the closer you are to retirement, the fewer years remain to fund that benefit, so each year’s contribution is larger.
That is why the strategy tends to suit owners in their late 40s, 50s and 60s, in their peak earning years. A 35-year-old with the same income may find a 401(k) does most of the job. A 58-year-old may find a plan allows a deduction several times larger. The specific figure comes from an actuarial feasibility study — never from a rule of thumb.
Why the calendar matters
The deduction belongs to a tax year, and the steps that create it have deadlines. Miss them and the opportunity for that year can narrow or disappear.
Earlier is better. A plan designed in October has options that a plan improvised in March does not.
- In the autumn: run the feasibility study while there is still time to act on it. It shows the estimated contribution range, the cost of covering any staff and the cash flow you will need.
- Before the last payroll of the year: if you own an S corporation, the plan generally counts your W-2 salary, not distributions. A salary set too low can limit the benefit, so the payroll decision belongs inside the plan, not after it.
- By December 31: ideally sign the plan document. Current law can allow a new plan to be adopted as late as your tax-filing deadline, including extensions — but a late start leaves less room to design it, adjust payroll or coordinate a 401(k).
- By your filing deadline: fund the contribution to deduct it for that year — generally by the tax-filing deadline, including extensions, often up to 8.5 months after year-end.
An illustrative example
Consider a hypothetical 58-year-old California owner of a small professional firm with two employees, earning around $600,000 a year and already maxing a 401(k). Suppose a feasibility study in October showed room for roughly $200,000 of additional deductible funding a year through a cash balance plan, including the cost of covering staff. At a combined state-and-federal marginal rate near 50%, that could defer on the order of $100,000 of tax in the first year — tax that is paid later, when the money is withdrawn. Had the same owner started the conversation after the year closed, that year’s payroll and 401(k) decisions would already be fixed, and the design would have less room to work. These figures are hypothetical and rounded, not a projection or a guarantee; any real number depends on an actuarial feasibility study.
Hypothetical and simplified, for illustration only — not a prediction or a guarantee. Real outcomes depend on your facts and on current law, which can change.
Who it tends to fit
A defined benefit plan is a multi-year commitment, so fit matters more than the size of the first-year deduction. As a rough guide, the owners it suits share a few traits:
Employees don’t rule it out. A cash balance plan paired with a safe-harbor 401(k) is often designed so the owners receive most of the funding while staff receive a controlled benefit that passes IRS testing. The staff cost belongs in the feasibility study, not in a surprise later.
- Profitable and steady — owner income of roughly $250,000 or more, year after year
- Age 45 or older, in the peak earning years
- Surplus cash flow that isn’t needed for lifestyle or reinvestment
- Willing to fund for roughly three to five years, or longer
- Few employees, or willing to fund a meaningful benefit for staff
The trade-offs to weigh
A deduction this size comes with obligations. They are manageable when planned for, and costly when they aren’t.
- Required funding. Each year the plan has a minimum contribution. If investment returns fall short of the plan’s assumptions, you may need to put in more.
- A long horizon. The IRS expects a qualified plan to be permanent. Ending one in its first few years without a genuine business reason can draw scrutiny.
- Money set aside for retirement. The funds are generally locked up until retirement, and early distributions can carry a penalty.
- Administration. An actuary, annual valuations, IRS testing and filings add cost that belongs in the math.
- Deferral, not elimination. The contribution is deductible now; the money is taxed when it comes out. The value lies in deducting at a high rate today and, ideally, withdrawing at a lower one.
Where it fits in the wider plan
A defined benefit plan rarely works alone. It lowers your taxable income, which can interact with the qualified business income (QBI) deduction, your bracket and your estimated payments — so the net saving should be modeled with your CPA, not assumed.
It also connects to decisions beyond this year. Owners planning a sale in the next few years sometimes use a plan to shelter income in the peak years before the exit; others pair it with nonqualified deferred compensation for key people. We model how the pieces stack, then coordinate the details with your CPA and attorney.
Common questions
Is this a permanent tax saving or a deferral?
A deferral. Contributions are deductible now and taxed when the money is withdrawn in retirement. The value comes from deducting at a high marginal rate in your peak years and, ideally, withdrawing at a lower rate later — with tax-deferred growth in between.
Can I still set up a plan after December 31 for last year?
Sometimes. Current law can allow a new plan to be adopted as late as your business’s tax-filing deadline, including extensions, and treated as in place for the prior year. But a late start limits the design — that year’s payroll and any 401(k) are already fixed — so year-end remains the better target. Confirm your specific deadlines with your CPA.
What if my income drops in a later year?
Plan for it at the start. Plans are often designed with a range between a required minimum and a deductible maximum, and future benefits can generally be reduced by amendment, with notice to participants. What these plans don’t handle well is a sudden stop in the first few years, which is why steady cash flow is part of the fit test.
See your number — before December 31.
Give us three inputs — owner age, income and headcount — and we’ll include a no-cost feasibility estimate in your Tax X-Ray. About 30 minutes, free, no obligation.
~30 minutes, free, no obligation.
The strategy behind this answer.
Defined Benefit & Cash Balance
Large deductible contributions — set up before year-end.
Keep reading.
Why the closing table is too late — and what to do now.
Depreciation recapture, the state tax, the 45- and 180-day deadlines, and when a DST beats another rental.
Ordinary income at vesting, capital gains after — and why your withholding is often too low before the vest date.
Educational only. This article is general information based on current law as of September 2026, which can change; it is not tax, legal or investment advice. All figures are hypothetical and illustrative, not a guarantee of any result, and IRS limits adjust annually. A defined benefit or cash balance plan’s maximum contribution is determined by an actuarial feasibility study. Please consult your CPA and attorney before acting.