What Retirement Plan Gives the Largest Tax Deduction for Business Owners?

For business owners seeking the maximum possible tax deduction through retirement plan contributions, the answer is clear -- a defined benefit plan, specifically a cash balance plan, provides the largest deduction of any retirement vehicle. When combined with a 401(k) profit-sharing plan, the total annual deduction can exceed $300,000 or more depending on age. No other plan type comes close.

Ranking the Plans by Maximum Deduction

Here is how the major retirement plan types compare in terms of maximum annual tax-deductible contributions for 2026.

A traditional IRA allows contributions of $7,000 ($8,000 if age 50 or older) under IRC Section 219(b)(5)(A). The deduction may be reduced or eliminated for taxpayers covered by an employer plan with AGI above certain thresholds under IRC Section 219(g). This is the lowest contribution limit of any retirement plan.

A SIMPLE IRA under IRC Section 408(p) allows employee deferrals of $16,500 ($17,850 with catch-up) plus employer matching up to 3% of compensation. Total contributions are relatively modest -- typically $20,000 to $30,000 depending on income and employer match structure.

A SEP IRA under IRC Section 408(k) allows employer-only contributions of up to 25% of compensation, capped at $70,000. There are no employee deferrals. For sole proprietors, the effective rate is approximately 20% of adjusted net self-employment income after the self-employment tax deduction.

A Solo 401(k) allows employee deferrals of $23,500 (plus catch-up contributions) and employer profit-sharing up to 25% of compensation. Total contributions can reach $70,000 to $81,250 depending on age. This is the maximum available from any defined contribution plan.

A defined benefit plan (cash balance plan) allows contributions determined by an enrolled actuary based on the participant's age, compensation, and target retirement benefit. Annual contributions can range from $80,000 to $350,000 or more. When combined with a 401(k), total annual contributions can exceed $400,000 for participants in their late 50s or 60s.

Why Defined Benefit Plans Allow Such Large Contributions

The contribution limits for defined benefit plans are driven by the maximum benefit the plan can provide at retirement -- not by a fixed dollar cap on contributions. Under IRC Section 415(b)(1)(A), the maximum annual benefit payable at age 62 or later is $280,000 per year (as indexed for 2026). The required annual contribution to fund that benefit depends on the participant's current age, the plan's assumed rate of return, and the number of years until retirement.

An older participant who starts a plan at age 55 with only 7-10 years until normal retirement age needs much larger annual contributions to accumulate enough to fund a $280,000 annual benefit than a younger participant with 30 years of funding ahead. This is why the contribution amounts increase dramatically with age -- the actuary must compress the funding into fewer years.

The Combined Plan Advantage

The IRS allows employers to sponsor both a defined contribution plan (401(k)) and a defined benefit plan (cash balance) simultaneously. The contribution limits for each plan type are independent -- governed by IRC Section 415(c) for defined contribution plans and IRC Section 415(b) for defined benefit plans. This means you can contribute the maximum to both plans in the same year, effectively doubling or tripling your total deduction compared to using a single plan.

The combined deduction is governed by IRC Section 404(a)(7), which provides that the maximum deduction for an employer maintaining both plan types is the greater of 25% of total compensation paid to plan participants or the minimum required contribution to the defined benefit plan. In practice, the cash balance plan's required contribution almost always exceeds 25% of compensation for the plan as a whole, ensuring the full deduction is available.

Tax Savings at Scale

To put the numbers in perspective, consider a 57-year-old business owner contributing $70,000 to a 401(k) profit-sharing plan and $230,000 to a cash balance plan -- a total of $300,000. At a combined federal and state marginal tax rate of 42%, the annual tax savings are $126,000. Over five years, that is $630,000 in tax savings -- money that would have gone to the government but instead compounds inside the retirement accounts.

Is This Strategy Right for You?

The defined benefit plan path to maximum deductions is ideal for business owners with sustained high income (above $400,000 annually), relatively few employees, age 40 or older (with increasing benefit for older participants), and willingness to commit to multi-year funding obligations. If your income is variable, you have many employees whose benefits would be costly to fund, or you need maximum flexibility in year-to-year contributions, a Solo 401(k) or SEP IRA may be the better standalone option -- sacrificing maximum deduction potential for simplicity and flexibility.

For business owners who meet the criteria, there is no question -- the defined benefit plan provides the largest tax deduction of any retirement plan, and combining it with a 401(k) profit-sharing plan maximizes the benefit to its fullest extent allowed under current law.

This article is for informational purposes only and does not constitute legal or tax advice. Consult a qualified tax professional regarding your specific circumstances. AE Tax Advisors, 935 Lake Elmo Dr, Suite B, Billings, MT 59105. Phone: (631) 614-5762.