Tax

The Solo Practitioner Retirement Stack: 401(k) + Cash Balance + DB

How high-income solo physicians, lawyers, and dentists combine multiple plans to shelter $300K+/year. The full stack with sequencing and trade-offs.

By Aparna Devalla, CPA3 min · 5 slidesUpdated July 26, 2026

1 / 5

Why Stacking Makes Sense

Single retirement plan caps don't reflect what high-income solo professionals can actually shelter.
Solo 401(k): up to $72K (2026 limit) with employee + employer.
Cash balance or defined benefit plan: stacked ON TOP of the 401(k), $100K–$250K additional shelter depending on age and comp.
Combined: $150K–$320K+ of tax-deferred shelter annually.
At top federal + state marginal rates, that's $60K–$130K+ of annual tax savings.

Layer Two: Cash Balance Plan

Hypothetical individual accounts with annual pay credits and interest credits.
Contribution capacity scales with age: a 55-year-old can credit dramatically more than a 35-year-old.
Typical contribution: $100K–$200K/year for owner-only plans at ages 45+.
Requires annual actuarial valuation ($3K–$5K).
Combined with Solo 401(k): the 401(k) handles employee deferral; the cash balance plan layers on top of the profit-share.

Layer Three: Defined Benefit Plan

Promise of a specified retirement benefit (e.g., 100% of comp at retirement).
Required funding calculated annually by actuary to meet projected benefit.
Older participants (50+) get dramatically higher contributions than younger.
Pure DB plans are less common than cash balance in solo settings, but for the right facts, they shelter even more.
Annual administrative cost: $4K–$8K including actuary, custodian, and TPA.

Stacking Order and Practical Limits

Step 1: max Solo 401(k) employee deferral ($24.5K).
Step 2: optimize Solo 401(k) employer profit-share within the combined $72K cap.
Step 3: layer cash balance OR defined benefit plan on top (subject to combined annual contribution limit rules).
Step 4: model the 415(c) and PBGC limits; high contributions face deduction limit and benefit accrual rules.
Best fit: solo professional with stable $400K+ annual income, age 45+, committed to multi-year contributions.
Need help architecting the full retirement stack? Rubric Financial coordinates the tax analysis and TPA referrals for solo high-income professionals; plan design and administration are handled by your actuary and TPA.

Use ← → keys or swipe on mobile

Educational content, not tax, legal, or accounting advice. Confirm with a CPA before acting.

On StartupCFO.AI: How to pay yourself as a startup founder

Accounting

Accrual Accounting: When to Switch From Cash Basis

Cash basis is simple but lies about timing. When accrual accounting is required, when it is simply the smarter call, and exactly how the switch works.

Accounting

Month-End Close Checklist for Small Businesses

A repeatable monthly close cadence, what to reconcile, what to accrue, and how to know your books are actually done.

Payroll

Multi-State Payroll Setup for Small Businesses

One remote employee in another state means new tax registrations, withholding rules, and compliance work. Here's the playbook.

Educational content, not tax, legal, investment, or accounting advice. See our Terms.

Previous in TaxOpportunity Zones: Capital Gain Deferral and Tax-Free Growth Next in Tax Section 1202 QSBS: Up to $15M Gain Tax-Free

Back to all resources

Want a CPA to own your filings?

Federal, state, and local returns prepared and reviewed by a licensed CPA, with the planning done before year-end rather than after it.

See tax and CPA services