1. How These Plans Differ From a 401(k)

A 401(k) is a defined contribution plan. The contribution is capped at a fixed dollar amount, $72,000 for 2026 under IRC Section 415(c), and the eventual retirement benefit depends on investment performance.
A defined benefit or cash balance plan works in reverse. It targets a specific annual retirement benefit, capped at $290,000 for 2026 under IRC Section 415(b), and an actuary calculates backward to determine what must be contributed each year to fund it. Because that calculation accounts for the owner's age, income, and years remaining until retirement, an older owner with fewer years to fund the benefit is required, and therefore permitted, to contribute far more annually than any defined contribution plan allows.
That is the entire mechanism behind the strategy. It is not a larger cap. It is a different kind of math.

2. Who This Strategy Fits

This works best for owners in their late 40s through 60s with consistent, high net business income who want to dramatically reduce current taxable income and are committed to funding the plan for several consecutive years, since these plans generally require more consistent annual funding than a 401(k).

3. Worked Example

A 55-year-old business owner with $500,000 of consistent net income has roughly ten years until a normal retirement age.
Because the actuary must fund a target benefit of up to $290,000 per year over a relatively short remaining horizon, the required annual contribution is large, and the full amount is deductible. For owners in this profile the deductible contribution commonly lands well into six figures, several times the $72,000 that a Solo 401(k) alone would permit.
The exact figure depends on age, income history, plan design, and the actuarial assumptions used, which is why this strategy always begins with a plan design study rather than a rule of thumb. What is consistent across every version of this analysis is the direction: the older the owner and the higher the stable income, the larger the deductible contribution becomes.

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4. Cash Balance vs. Solo 401(k): A Comparison
 

5. Combining With a Solo 401(k)

These plans are often layered on top of a Solo 401(k) rather than used instead of one, allowing a business owner to contribute the Solo 401(k) maximum and then add the cash balance contribution on top — pushing total tax-deferred savings well beyond what either plan offers alone.

6. Step-by-Step Checklist

• Confirm consistent, sufficiently high net business income to support the strategy
• Engage an actuary to calculate the required contribution
• Establish the plan before year-end
• Confirm ability to fund the plan consistently for multiple years
• Layer with a Solo 401(k) if maximizing total contribution is the goal
• Review plan design annually as income or staffing changes

7. Most Common Mistakes

Setting up the plan without modeling multi-year commitment. These plans assume relatively consistent funding — a business with volatile income should model this carefully first.

Not combining with a Solo 401(k). Owners sometimes choose one or the other when layering both maximizes total deductible savings.

Underestimating the cost of plan administration. The actuarial and administrative cost is higher than a Solo 401(k), and should be weighed against the additional tax savings.

Wondering if this strategy applies to your business? Book a free strategy call with our team

8. FAQ

At what age does this strategy make the most sense? Generally 45 and older, since the actuarial math allows older owners closer to retirement to contribute significantly more.

Can I have employees and still use this strategy? Yes, but the plan must generally cover eligible employees as well, which adds cost — this is a key part of the modeling process.

Is this a good fit for a business with unpredictable income? Not usually — the funding consistency required makes this strategy best suited to stable, high-income businesses.