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Originally reported by 24/7 Wall St. via Google News.
The Evidence
$111,000. That is the federal income tax a 58-year-old orthodontist earning $500,000 in net practice income can legally eliminate in a single calendar year — without offshore accounts, corporate restructuring, or loopholes. The mechanism has existed in the U.S. tax code for decades, but as of June 22, 2026, only about 16% of small businesses use it, according to financial advisory data cited by 24/7 Wall St. The strategy: stack a cash balance defined benefit plan on top of a Solo 401(k), converting what most practitioners treat as a single-account retirement system into a two-plan engine that can absorb $232,500 to $282,500 in annual tax-deductible contributions.
A Solo 401(k) — the standard retirement vehicle for self-employed professionals — allows total contributions of up to $72,000 in 2026, combining employee deferrals and employer profit-sharing. That figure rose from $70,000 in 2025 per IRS Notice 2025-67, issued in November 2025. On its own, it is a solid personal finance tool, but it barely moves the needle for someone in the 37% federal bracket. The cash balance plan is what changes the calculus. This type of defined benefit plan (a pension structure that credits each participant's account with a guaranteed fixed annual amount rather than linking the balance to market performance) allows contributions of $100,000 to $275,000 or more annually, with the ceiling rising sharply with age. At 58, the window opens widest.
The Math: Running the Numbers
Chart: 2026 annual retirement contribution comparison for a 58-year-old high-income professional — Solo 401(k) maximum alone, cash balance plan contribution at age 58, and the combined two-plan total.
For a 58-year-old orthodontist with $500,000 or more in net practice income, the 2026 contribution breakdown looks like this: approximately $32,500 to a Solo 401(k) — the $24,500 employee deferral plus an $8,000 catch-up contribution for participants aged 50 and older — combined with $200,000 to $250,000 to a cash balance plan, for a total annual deduction of $232,500 to $282,500.
Apply the 37% federal marginal tax rate and a $300,000 combined contribution saves $111,000 in federal income taxes in the contribution year alone. State income taxes add another $15,000 to $30,000, bringing potential single-year tax relief to $126,000 to $141,000. The IRS increased the maximum defined benefit plan annual benefit under IRC Section 415(b) to $290,000 for 2026, up from $280,000 in 2025 — enabling cash balance contributions of up to approximately $435,250 for the oldest, highest-income participants. These are the IRS's own published limits from Notice 2025-67, not projections.
Retirement planning specialists at Emparion describe the two-plan dynamic this way: “The highest levels of contributions, tax deductions and flexibility come when the two plans work together... By layering a Cash Balance Plan on top of your Solo 401(k), you can multiply your annual savings — often two to three times the 401(k) limit.” Physician and dentist tax planning guides at Taxstra describe cash balance plans as “the secret weapon of high-income physicians” — which makes the 16% adoption rate among small businesses feel less like a strategy gap and more like a systemic failure of professional financial planning education.
The deferred tax doesn't vanish — it becomes ordinary income when withdrawn in retirement, presumably at a lower effective rate. The wager embedded in this structure: that a practitioner currently earning $500,000 annually will face meaningfully lower marginal rates at 70 or 75 when drawing down assets. For most practitioners who wind down practice income gradually, that bet has historically paid off.
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What It Means for Independent Practice Owners
The numbers stand alone, but the demographic picture adds genuine urgency. As of 2024, the average retirement age for dentists reached 68.7 years, up from 64.7 in 2001 — a shift driven by education debt, practice startup costs, and equipment financing that consumed the years when compounding delivers the most. A practitioner who spent their 30s building a business rather than an investment portfolio now faces a narrowing window and needs an accelerated contribution vehicle.
Dental Service Organization (DSO) affiliation reached 16.1% as of 2024, and only 73% of dentists now own their practices, down from 85% in 2005. For independent owners competing against corporate models, the two-plan structure represents a structural financial planning advantage that DSO-employed practitioners generally cannot replicate at the same scale — making it one of the few remaining structural edges that independent practice ownership still provides.
Multiple financial advisory sources note that once a practice generates approximately $300,000 or more in Schedule C income, “the benefits of deferral that a cash balance plan offers begin to outweigh the costs of creating and administering the plan.” Those costs are real but quantifiable: setup runs $2,000 to $5,000, annual administrative and actuarial fees run $2,000 to $10,000, and investment management fees add 0.25% to 1% of assets. Against $111,000 in annual federal tax savings, the cost structure is manageable for most qualifying practices.
AI investing tools and retirement planning software have made it easier to model these scenarios precisely — projecting the compounding difference between taxed and tax-deferred capital across a 10-to-15-year horizon before the first dollar is committed. In my analysis, the most underappreciated dimension of this strategy is not the immediate tax saving — it is the compounding effect of deploying pre-tax dollars at scale. At a 7% real return, $282,500 invested today grows to roughly $635,000 over 12 years before taxes, versus roughly $178,000 in net after-tax capital if that same income had been taxed at 37% first. That gap — not the stock market today, not a well-timed trade — is where lasting wealth is actually built.
How to Act on This
Cash balance plans work best for practices with fewer than 10 employees and stable cash flow of $100,000 or more in annual profits, according to multiple financial advisory sources. The employer must fund the plan annually regardless of business performance — that mandatory contribution obligation is the central risk. If your practice income varies significantly year to year, model the minimum required contribution under a bad-revenue scenario before committing to the plan design.
An enrolled actuary — a licensed specialist required by federal law to certify defined benefit plans — must calculate the specific annual cash balance contribution available based on your age, compensation history, and the plan's crediting rate. As of June 22, 2026, the IRS maximum defined benefit annual benefit under IRC Section 415(b) stands at $290,000, but the contribution ceiling that applies to your individual situation requires actuarial calculation. A CPA alone is not sufficient for plan design.
The Solo 401(k) and cash balance plan must be designed together under IRS rules — specifically the combined limits under IRC Section 415. A third-party administrator (TPA) specializing in defined benefit plans handles annual compliance filings and actuarial valuations. The administrative cost of $2,000 to $10,000 annually is itself a fully tax-deductible business expense, reducing the net out-of-pocket cost further and improving the strategy's already-favorable economics.
Frequently Asked Questions
How much can I save in taxes with a cash balance plan and 401(k) combined in 2026?
At the 37% federal marginal tax rate, a combined $300,000 deduction across a Solo 401(k) and cash balance plan saves $111,000 in federal income taxes in the contribution year, according to financial advisory data reported by 24/7 Wall St. State income tax savings add another $15,000 to $30,000, bringing potential single-year tax relief to $126,000 to $141,000. The exact figure depends on your age, net practice income, state of residence, and plan design.
Can I legally have both a 401(k) and a cash balance plan at the same time?
Yes. The IRS permits layering a cash balance defined benefit plan on top of a Solo 401(k) for self-employed professionals and small business owners. As of June 22, 2026, the Solo 401(k) allows total contributions up to $72,000 per IRS Notice 2025-67, while the cash balance plan adds $100,000 to $275,000 or more depending on age and income. The two plans must be designed as coordinated plans under IRC Section 415's combined limits — which is why both an enrolled actuary and a TPA are essential, not optional.
What is the downside of a cash balance plan for a small dental or medical practice?
The primary risk is mandatory annual funding — the employer must contribute to the plan every year regardless of business performance, unlike a 401(k) where contributions are discretionary. Setup costs run $2,000 to $5,000, and ongoing administrative and actuarial fees add $2,000 to $10,000 annually. Investment management fees add another 0.25% to 1% of plan assets. The strategy is best suited to practices with stable income exceeding $100,000 in annual profits and fewer than 10 employees.
How does a cash balance plan work specifically for dentists and orthodontists?
A cash balance plan establishes a hypothetical account for each participant and credits it annually with a fixed contribution — typically a percentage of compensation or a flat dollar amount — plus a guaranteed interest rate set by the plan document. The employer funds the entire plan, and all contributions are tax-deductible. For a 58-year-old orthodontist with $500,000 in net practice income, the plan can accommodate $200,000 to $250,000 in annual contributions. According to multiple financial advisory sources, most dentists and orthodontists can make total tax-deductible cash balance contributions of $100,000 to $300,000 annually — far exceeding what standard 401(k) limits alone permit.
- As of June 22, 2026, combining a Solo 401(k) (up to $72,000) with a cash balance plan ($100,000–$275,000+) allows a 58-year-old orthodontist to deduct $232,500 to $282,500 annually, per IRS Notice 2025-67.
- At the 37% federal marginal rate, a $300,000 combined deduction eliminates $111,000 in federal income taxes in the contribution year alone — with state savings adding $15,000–$30,000 more.
- Only about 16% of small businesses currently use cash balance plans despite these benefits, making this a legally available but systematically underused retirement strategy.
- Mandatory annual contributions regardless of business performance are the central risk; the strategy works best for practices with stable cash flow above $100,000 in annual profits and fewer than 10 employees.
Disclaimer: This article is for informational and educational purposes only and does not constitute financial, tax, or legal advice. IRS contribution limits, tax laws, and plan rules are subject to change. Consult a licensed CPA, enrolled actuary, and qualified financial advisor before implementing any retirement plan strategy. Research based on publicly available sources current as of June 22, 2026.