For many Americans approaching retirement, the core question is no longer “Will there be enough income?” but “How should existing income and savings be structured for taxes, healthcare costs, and heirs?”. When pensions, Social Security, and investment income together already cover expenses, Roth conversions and account placement become tools for shaping passive income, not for plugging gaps.
The Building Blocks of Passive Income
A typical pre‑retiree balance sheet includes several income and asset sources:
Employer pensions and Social Security, often with built‑in inflation adjustments.
Tax‑deferred accounts such as 403(b)s, 401(k)s, and traditional IRAs.
Smaller Roth IRAs or Roth 401(k)s.
Taxable investment accounts and potential inheritances.
Pensions and Social Security provide a guaranteed, inflation‑linked base. Tax‑deferred and Roth accounts add flexibility: they can generate ongoing investment income (dividends, interest) and fund withdrawals, but each has different tax consequences. The question is how much to shift from tax‑deferred to Roth, and over what time horizon, to create stable passive income with manageable tax and healthcare costs.
Roth Conversions: Three Strategic Paths
Roth conversions move assets from tax‑deferred to tax‑free status by paying income tax today. For households with strong guaranteed income, three broad approaches exist:
Aggressive conversion. Converting a large share of tax‑deferred assets over a short period, accepting a high current tax bill to reduce future required minimum distributions (RMDs) and future taxable withdrawals.
Gradual, multi‑year conversion. Making smaller annual conversions sized to stay within chosen tax and Medicare premium brackets, using projections to avoid “cliff” effects.
Minimal or no conversion. Leaving most assets in tax‑deferred form, letting RMDs drive future withdrawals, and accepting the associated tax profile.
The trade‑off is between paying known tax today and potentially higher—but uncertain—tax later. For retirees already in higher brackets due to pensions, large conversions can push marginal rates and healthcare surcharges significantly higher in the short term, which is why aggressive strategies are often less compelling at this stage.
Tax Brackets, IRMAA, and Healthcare Costs
For Medicare‑eligible retirees, Roth conversion sizing is constrained not only by income‑tax brackets but also by Medicare’s income‑related monthly adjustment amount (IRMAA). IRMAA surcharges apply when modified adjusted gross income (MAGI) exceeds tiered thresholds and can add thousands of dollars per year to Part B and Part D premiums.
Every dollar converted from a traditional account to a Roth counts as ordinary income in the year of conversion, raising MAGI. Because IRMAA uses a two‑year lookback—current premiums are based on income from two years prior—a conversion today can trigger higher premiums later, after the tax decision is irreversible.
In practice, this leads many high‑income retirees to favor gradual conversions that keep total income within a selected IRMAA tier. Converting just enough to stay below the next threshold, and stopping several thousand dollars short to allow for unexpected income, helps avoid sudden premium jumps.
Estate Planning and the SECURE Act
Roth conversions also interact with inheritance rules. The SECURE Act requires most non‑spouse beneficiaries of traditional and Roth IRAs, as well as inherited 401(k)s and 403(b)s, to fully deplete the accounts within 10 years of the original owner’s death.
For inherited traditional accounts, those withdrawals are taxed as ordinary income. For inherited Roth accounts, qualified distributions are generally tax‑free, and there are no annual minimums during the 10‑year window. A beneficiary can allow an inherited Roth to compound tax‑free and then withdraw the entire balance in year ten without federal income tax.
This “compressed 10‑year window” often creates a tax spike for heirs of large traditional accounts, especially if those withdrawals stack on top of their own salaries. Converting a portion of traditional assets to Roth during the original owner’s lifetime, especially when outside cash is available to pay the conversion tax, can reduce that future burden.
Opportunity Cost and Market Risk
Roth conversions involve opportunity cost: tax dollars paid now could have remained invested. For retirees with sizable portfolios, market behavior around conversion dates matters. Converting heavily just before a significant market decline means paying tax on a higher balance and then watching that value fall, which reduces the effective benefit of the conversion.
Conversely, converting in weaker markets lowers the immediate tax bill per dollar of future Roth growth. Many planners therefore favor modest conversions later in the tax year—when income is known—and during periods of lower asset values, rather than committing to a single large conversion based on one year’s conditions.
Designing an Account Structure for Passive Income
For U.S. residents approaching or in early retirement, an account structure aimed at passive income and tax control often looks like this:
Guaranteed‑income layer. Pensions and Social Security form the core, covering essential expenses.
Tax‑deferred growth and income layer. Traditional IRAs and employer plans hold diversified portfolios, often with a meaningful dividend and interest component to support RMDs and optional withdrawals.
Tax‑free flexibility layer. Roth accounts are built up gradually through planned conversions, financed where possible by non‑retirement cash, and invested in assets expected to benefit from long‑term, tax‑free compounding.
Liquidity layer. Taxable accounts and cash reserves manage near‑term spending and unexpected needs, reducing pressure to alter retirement account strategies during volatile periods.
Within this framework, dividends and other investment income contribute to passive cash flow, but they do so inside an intentional tax and healthcare structure. The goal is not to eliminate volatility or taxes, but to ensure that when markets move or rules shift, the household is not forced into reactive decisions.
Why Multi‑Year Planning Often Fits Late‑Career Retirees
For pre‑retirees with strong pensions and large tax‑deferred balances, research generally finds that disciplined, multi‑year Roth conversion plans can add value by smoothing tax burdens and protecting heirs, while aggressive one‑time conversions carry higher risk and fewer advantages.
Sizing conversions to tax and IRMAA thresholds, coordinating them with portfolio risk and expected returns, and viewing them in the context of the entire balance sheet turns Roth decisions into part of a broader passive‑income design. In that design, the most durable outcomes come less from dramatic moves and more from steady adjustments that respect both the math and the constraints of the retirement system.