Cash Balance Plan for Dentists: Shelter $100K–$290K+ Per Year

The solo 401(k) limit in 2026 is $72,000 — $80,000 with catch-up contributions if you're over 50. For a dentist netting $400,000 or more, that's a meaningful deduction, but it still leaves $320,000+ per year exposed to federal income tax at the 32–37% bracket. A cash balance plan — layered on top of the 401(k) — can shelter an additional $80,000 to $290,000 per year, all fully deductible, all growing tax-deferred. This is the strategy behind the dental practice owners who report very low effective federal tax rates despite high incomes.

What is a cash balance plan?

A cash balance plan is an IRS-qualified defined benefit pension plan — but it works differently from a traditional pension. Instead of promising a fixed monthly benefit at retirement, it maintains a hypothetical individual account for each participant. Each year, the plan credits two things to your account:

• A pay credit: A percentage of your compensation (the main "contribution"), set by the plan design.
• An interest credit: A guaranteed crediting rate, typically tied to a fixed rate (3–5%) or a benchmark like the 30-year Treasury yield. This rate is set in the plan document, not by the market.

At exit, you can roll the entire balance into an IRA — just like a 401(k). The money grows tax-deferred until withdrawal.

How much can a dentist contribute?

The short answer: it depends on your age, income, and how close you are to retirement. The plan must be designed by a credentialed actuary, who certifies the annual contribution needed to fund the promised benefit within IRS limits.

The governing limit is §415(b), which caps the maximum annual benefit the plan can eventually pay at $290,000 per year (2026, per IRS Notice 2025-67¹). A participant who is older has fewer years for contributions to compound, so the IRS allows higher annual contributions to reach the same funded status. This makes cash balance plans especially powerful for dentists aged 45 and older.

These ranges are illustrative. Your actuary calculates the exact contribution based on your plan's target benefit and interest crediting rate — actual amounts will vary.

The 2026 defined contribution limit (§415(c)) that applies to your 401(k) is $72,000, increasing to $80,000 with the age-50+ catch-up, and $83,250 with the SECURE 2.0 age-60–63 super catch-up.¹ These limits are entirely separate from the cash balance §415(b) limit — you can max both in the same year.

The stacking strategy: solo 401(k) + cash balance

In practice, dental practice owners run both plans simultaneously. The solo 401(k) fills first — it's simpler, cheaper to administer, and completely flexible year to year. The cash balance plan adds the large additional deduction on top.

Here's a worked example of a 52-year-old S-corp dentist paying herself a $200,000 W-2 salary on $480,000 of practice net income:

At a combined federal + state marginal rate of 40%, sheltering $265,000 per year saves approximately $106,000 in taxes annually. Over a 10-year window from age 52 to 62, the plan accumulates over $2.6 million pre-tax, even before investment growth.

Who this strategy fits

Cash balance plans are powerful but not universal. The math works best for:

• Practice owners netting $300K or more. Below that, the fixed TPA and actuarial costs consume a larger share of the tax savings. At $500K+ net, the plan is almost always worth it.
• Ages 45 and up. You can start earlier, but the contribution limits scale up sharply with age. Dentists in their 50s see the biggest benefit.
• Solo practitioners and small-ownership practices. If your practice has significant W-2 staff, the plan must cover them too — this adds cost and can dilute the benefit. Pure solo practitioners or two-partner practices with minimal staff get the cleanest economics.
• Stable income dentists, not purely production-based associates. Cash balance plans have mandatory minimum contribution ranges each year. If practice income swings dramatically, a plan with high required contributions can create cash-flow problems in a slow year. Owners with predictable collections are the best fit.
• Dentists not planning to exit in the next 3 years. The plan can be frozen and eventually terminated if you sell, but there's administrative complexity. Plans work best with a 5–10 year runway.

Setup and ongoing costs

Running a cash balance plan has real costs. Here's what to budget:

At $185,000 in annual contributions and a 37% federal rate, the tax saving is roughly $68,450 per year. The $5,000 administration cost is 7.3% of that saving — a very favorable ratio. At $100,000 in contributions, the ratio is less attractive but typically still worthwhile.

Important rules to know

Mandatory contribution range

Unlike a 401(k), where you can contribute $0 in a bad year, a cash balance plan requires you to fund within an actuarially determined range each year (typically your target contribution ± 10–15%). If practice income dips severely, you must still make minimum contributions to keep the plan compliant. This is why income stability matters when evaluating fit.

The 2026 Roth catch-up rule (SECURE 2.0)

Starting in 2026, dentists earning more than $150,000 in prior-year FICA wages must make their 401(k) catch-up contributions as Roth (after-tax) rather than pre-tax.² This rule applies to the 401(k) catch-up piece only — cash balance plan contributions remain pre-tax regardless. For high earners, the cash balance plan becomes even more valuable because it's one of the few large pre-tax mechanisms that isn't affected by the Roth catch-up mandate.

Employee coverage

If your practice has non-owner W-2 employees who work 1,000+ hours per year, the plan's coverage and nondiscrimination rules require you to include them on some basis. The TPA models this; sometimes it's economically efficient to include lower-compensated staff (their required contribution is much smaller), sometimes the math doesn't work. This is the key underwriting question before you establish the plan.

How to implement

The critical deadline: the plan must be established by December 31 of the tax year you want to deduct contributions. Contributions themselves can be made up to the tax filing deadline including extensions (October 15 for most practice owners on extension). This means if you're reading this in the fall, you still have time to establish the plan and fund it in one action before year-end.

Steps:

1. Assess fit with a fee-only advisor who has cash balance experience. They'll model whether the math works for your practice structure, income level, and timeline.
2. Select a TPA with actuarial capabilities. The advisor typically has relationships with TPAs who specialize in this type of plan for professional practices.
3. Sign the plan document. This must be signed by December 31. The TPA drafts it; you sign.
4. Fund the plan. The actuary certifies the contribution amount. You write a check from the practice — it's a deductible business expense.
5. Invest the plan assets. The cash balance plan holds assets in a trust, often invested conservatively relative to the guaranteed crediting rate. Your advisor or TPA manages this.