For years, the Roth conversion conversation was dominated by one looming deadline: the 2025 sunset of the Tax Cuts and Jobs Act. Advisors urged clients to "convert before rates go up." That deadline has now passed — and the picture has changed. The One Big Beautiful Bill Act (OBBBA) made the seven TCJA tax brackets permanent at 10%, 12%, 22%, 24%, 32%, 35%, and 37%. The artificial urgency is gone, but the underlying case for Roth conversions in retirement has not weakened. It has simply shifted from a race against the calendar to a steadier, multi-year planning problem.
What a Roth Conversion Actually Does
A Roth conversion moves pre-tax dollars from a traditional IRA or 401(k) into a Roth IRA. The amount converted is added to ordinary income for that year, taxed at the investor's marginal rate, and then grows tax-free for the rest of their life — and, under current rules, for ten years inside the accounts of most non-spouse heirs. There are no income limits on conversions and no annual cap on the amount converted, which is what makes the strategy useful for retirees with large pre-tax balances.
Why the 65-to-73 Window Is So Valuable
The most efficient time to convert is rarely during peak earning years. It's the gap between when wages stop and when required minimum distributions (RMDs) begin at age 73 (rising to 75 for those born in 1960 or later). During this stretch, taxable income is often at its lowest of an investor's adult life: paychecks are gone, Social Security may be deferred, and RMDs have not yet forced large pre-tax withdrawals.
That low-income window is what creates room to "fill a bracket." A married couple in 2026 with a $32,200 standard deduction and modest pension or interest income may have headroom of tens of thousands of dollars before crossing from the 12% into the 22% bracket, and substantially more before reaching 24%. Converting just enough each year to top off a target bracket — without spilling into the next one — is the core mechanic of a multi-year conversion ladder.
The IRMAA Trap Most People Miss
Income-Related Monthly Adjustment Amounts (IRMAA) are Medicare Part B and Part D surcharges triggered by modified adjusted gross income. Two features make them especially relevant to conversion planning. First, they're cliffs, not phase-ins: crossing a threshold by a single dollar moves you to the next surcharge tier. Second, they look back two years, so a conversion done in 2026 affects 2028 premiums. The first IRMAA cliff for married filers begins at $212,000 of MAGI. Crossing it raises Part B premiums by roughly $74 per month, per person — meaningful drag on a retirement income plan.
Capable conversion planning means modeling IRMAA tiers alongside federal brackets, not just one or the other.
Where Diversification Fits In
Roth conversions are a tax-location decision, not an investment decision — but the two interact. Retirees often hold their highest-growth and most volatile assets, including equities and alternatives like precious metals, in accounts where future appreciation will compound tax-free for decades. A Roth IRA is one of the few accounts where that combination works without future tax friction. Investors who hold gold or other diversifying assets through a self-directed Roth IRA receive the same tax treatment as any other Roth holding, with appreciation and qualified withdrawals exempt from federal income tax.
Practical Takeaways
- The window matters more than the deadline. With TCJA rates permanent, the urgency is no longer "before 2026." It's "before RMDs and Medicare surcharges constrain you."
- Model the full income picture. A conversion strategy that ignores Social Security, pensions, capital gains, and IRMAA tiers will mis-size the bracket-fill.
- Convert in measured slices. Filling the 12%, 22%, or 24% bracket annually over multiple years usually beats one large conversion that pushes income into a higher tier.
- Coordinate with diversifying assets. If a portion of the retirement portfolio is allocated to precious metals or other volatile diversifiers, the Roth side is often the most tax-efficient place to hold the long-term growth portion.
The Roth conversion is no longer a one-time TCJA-driven event. In the post-OBBBA environment, it's an ongoing piece of retirement income engineering — one whose payoff comes from disciplined sizing across the years before RMDs take that flexibility away.
Sources: IRS, Tax Foundation, Charles Schwab, U.S. Bank, Boldin, Income Laboratory, Saxon Financial Group