The Backdoor Roth Pro-Rata Rule: The Trap Physicians Hit

How the rule works

When you convert money from a traditional IRA to a Roth IRA, the IRS does not let you designate which dollars you are converting. It aggregates every traditional, SEP, and SIMPLE IRA you own and computes one ratio across all of them.

The taxable portion is the conversion amount multiplied by pre-tax balance divided by total IRA balance. If you have $7,500 of after-tax basis and a $142,500 pre-tax rollover IRA, your total is $150,000 and only 5% of any conversion is tax-free. The other 95% is ordinary income at your marginal rate, which for an attending physician is generally 32% or higher.

Why physicians hit this more than most people

The typical path runs through residency. A resident contributes to a 403(b) at their training institution, leaves for fellowship or a first attending job, and rolls that balance into a traditional IRA because a broker or an online article suggested it. That rollover IRA sits there for years.

Then the physician's income crosses the Roth contribution limit, someone recommends a backdoor Roth, and the forgotten rollover IRA silently makes almost all of it taxable. The money was never lost, but the strategy did not do what the physician thought it did, and the tax bill arrives a year later.

The December 31 measurement date

The aggregation is calculated using your total IRA balances on December 31 of the year in which the conversion occurred, not on the date of conversion. That timing detail is what makes the fix possible and also what makes procrastination expensive.

A physician who converts in February and clears their pre-tax IRA balance by December 31 of the same year is fine. A physician who converts in February and still holds the rollover IRA on December 31 is not, even though the conversion happened first.

The standard fix

IRA aggregation excludes employer retirement plans. Your 401(k), 403(b), and TSP balances do not enter the calculation at all. So the common remedy is a reverse rollover: move the pre-tax IRA balance into your current employer's 401(k) or 403(b), if the plan accepts incoming rollovers, which zeroes your traditional IRA balance before year end.

Not every plan accepts them, and plan investment menus vary in quality, so this is a decision with a trade-off rather than an automatic yes. Check whether your plan accepts rollovers, compare the expense ratios, and confirm the transfer is complete well before December 31 rather than in the last week of the year.

• Inventory every traditional, SEP, and SIMPLE IRA you own, including old ones
• Confirm your employer plan accepts incoming rollovers
• Complete the reverse rollover with margin before December 31, not on it
• Compare plan expense ratios before moving the money
• File Form 8606 for the year of the non-deductible contribution and the conversion

Form 8606 is not optional

Form 8606 is how you report non-deductible basis and prove the conversion was not fully taxable. If you skip it, the IRS has no record of your after-tax basis and will generally treat the entire conversion as pre-tax income.

This is a common failure even among physicians who executed the strategy correctly, particularly when a tax preparer was not told a backdoor Roth occurred. Check that the form was filed for every year you did one, and keep copies indefinitely; basis carries forward.

When the backdoor Roth is not worth the trouble

If you have a large pre-tax IRA balance and your employer plan will not accept a rollover, the pro-rata drag may make the strategy not worth executing in that year. Converting the whole balance is an option but generates a large tax bill at your top marginal rate.

In that case the more productive move is often to focus on filling the 403(b), 457(b), and any mega backdoor Roth capacity first, and revisit the IRA question when you change employers and gain access to a plan that accepts rollovers.

Related physician planning questions

What is the pro-rata rule for a backdoor Roth?

Under IRC §408(d)(2), all your traditional, SEP, and SIMPLE IRAs are aggregated into one pool when calculating the taxable portion of a conversion. Pre-tax and after-tax dollars come out proportionally. The taxable portion equals the conversion amount times pre-tax balance divided by total IRA balance.

Do 401(k) and 403(b) balances count toward the pro-rata rule?

No. IRA aggregation excludes employer retirement plans, so 401(k), 403(b), and TSP balances are not included. This is why rolling a pre-tax IRA into an employer plan before year end is the standard fix.

When is the IRA balance measured for pro-rata purposes?

On December 31 of the year in which the conversion occurred, not on the conversion date. A physician who converts in February and clears the pre-tax IRA by December 31 of the same year avoids the pro-rata drag.

What happens if I don't file Form 8606?

Without Form 8606 the IRS has no record of your non-deductible basis and will generally treat the entire conversion as taxable pre-tax income. File it for every year you make a non-deductible contribution or a conversion, and retain copies, since basis carries forward across years.

What is the 2026 IRA contribution limit?

$7,500 for 2026, up from $7,000, with a $1,100 age-50 catch-up for a combined $8,600.

Related insights

• Backdoor Roth IRA for Physicians
• Can Residents Use a Backdoor Roth IRA?
• Mega Backdoor Roth for Doctors
• Browse the full archive

Sources

• Kitces.com — Effective Backdoor Roth Strategy: Rules, IRS Form 8606 (accessed August 2026)
• Internal Revenue Service — 401(k) limit increases to $24,500 for 2026, IRA limit increases to $7,500 (accessed August 2026)

Figures current as of August 7, 2026. Contribution limits, tax thresholds, and federal loan program rules change; verify against the primary source before acting.

See how this fits into a physician-focused plan.

Attend Wealth helps physicians connect planning, taxes, investing, insurance, and retirement decisions into one strategy. If you want help applying this topic to your own loans, taxes, investments, or retirement plan, schedule a complimentary conversation.

This article is for educational purposes only and is not personalized financial, tax, or legal advice. Attend Wealth is a registered investment adviser and acts as a fiduciary to its advisory clients. Attend Wealth is fee-based: in addition to advisory fees, our advisors are licensed insurance professionals and may receive commissions on insurance policies placed through carriers including Guardian, MassMutual, Ameritas, Principal, The Standard, and Lloyd's. That compensation creates a conflict of interest. We describe it, and how we address it, in our Form ADV Part 2A and Form CRS, available at adviserinfo.sec.gov or on request. Please consult a qualified professional about your specific situation.