Tax

Defined Benefit & Cash Balance Plans for High-Income Solo Owners

When Solo 401(k) and SEP-IRA caps aren't enough, defined benefit and cash balance plans can shelter $200K–$300K+ per year. Here's when they make sense.

By Aparna Devalla, CPA3 min · 5 slidesUpdated June 15, 2026

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When You've Outgrown Solo 401(k) and SEP

Solo 401(k) and SEP-IRA both cap at ~$69K/year (2024 limits). For high-income solo professionals, that's still leaving $100K+ on the table.
Defined benefit (DB) plans calculate contributions based on the actuarial cost of providing a target retirement benefit — not a fixed dollar cap.
Cash balance plans are a hybrid: defined-benefit structure with individual account balances. Easier to communicate, more portable.
Both let high-income solo owners shelter $150K–$300K+ in pre-tax contributions annually.

Who Benefits Most

Solo practitioner physicians, dentists, lawyers, and consultants with stable annual profit above ~$300K.
Owner-only businesses (no W-2 employees, or only spouse). Adding employees triggers complex non-discrimination rules and ongoing actuarial cost.
Age matters: contribution limits scale with age. A 55-year-old solo owner can shelter dramatically more than a 35-year-old.
Best for owners committed to multi-year contributions — DB plans require ongoing funding once established, with limited flexibility to skip years.

Mechanics of a Cash Balance Plan

Plan document defines the 'hypothetical account' for each participant — annual credit + interest credit.
Owner-only plan: contributions calculated to meet the projected retirement benefit, typically 100–200% of comp depending on age.
Combined with Solo 401(k): the 401(k) handles employee deferral + employer match; the cash balance plan layers on top.
Investment risk is on the plan (the owner) — not the participant. Returns above the interest credit benefit the owner; shortfalls require additional funding.

When to Stop or Wind Down

Adding non-spouse employees: cash balance plans must satisfy non-discrimination rules; owner contribution capacity drops sharply.
Multi-year profit drop: the funding obligation continues; may need to amend or freeze the plan.
Selling the practice: typically freeze plan benefits at sale date, distribute or roll over balances.
Plan termination: requires PBGC filings (for covered plans), participant distribution, IRS Form 5310 application — complex, take 12–18 months.
Considering a defined benefit or cash balance plan? Rubric Financial coordinates plan selection, TPA referrals, and ongoing administration with our fractional CFO and tax engagements.

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