The 401(k) bracket smoothing strategy that keeps retirees out of the 22% tax bracket for life

A 66-year-old single woman, retired, with $1.1 million in a traditional 401(k), $300,000 in a Roth IRA, and $200,000 in a taxable brokerage faces the same question every retiree eventually confronts: which account do I tap first? The conventional answer, taxable first, then tax-deferred, then Roth, costs her roughly $74,000 in lifetime federal income tax. A different withdrawal sequence, one almost no financial planner volunteers, closes most of that gap.

Her spending target is $72,000 a year. Social Security begins at 67 at $30,000. Two withdrawal sequences produce two very different lifetime tax bills.

Sequence A: The conventional drawdown

Sequence A spends the $200,000 brokerage account from age 66 through roughly 69, then shifts to the 401(k). Social Security layers in at 67. By the time required minimum distributions begin at 73, the 401(k) has compounded to or above its starting balance. The mandatory withdrawal stacked on top of Social Security pushes her taxable income persistently into the 22% bracket and keeps it there through her 80s.

Modeled across ages 66 to 90, federal income tax under this path totals approximately $186,000. Up to 85% of her Social Security benefit becomes taxable in most of those years, and a single year of unusually large RMDs can clip the first IRMAA tier two years later.

Sequence B: Bracket smoothing before RMDs

Sequence B inverts the order during the early retirement window. From age 66 through 72, she draws $40,000 a year from the 401(k) and $32,000 from the Roth IRA. The 401(k) withdrawal, combined with the 2026 standard deduction of $18,150 available to a single filer aged 65 or older (the $16,100 base plus the $2,050 age add-on), lands her taxable income comfortably inside the 12% bracket. The Roth fills the rest of her $72,000 spending need, entirely tax free.

The brokerage sits untouched. By 73, the 401(k) balance is materially smaller, so her RMD plus Social Security mostly stays within the 12% bracket for the rest of her life. Lifetime federal tax comes to approximately $112,000, a saving of roughly $74,000 compared with Sequence A.

A new senior deduction worth knowing

The One Big Beautiful Bill Act, signed July 4, 2025, added a meaningful wrinkle for this retiree. For tax years 2025 through 2028, filers aged 65 or older can claim an additional $6,000 deduction on top of the standard deduction. The provision phases out at a rate of 6% for every dollar of MAGI above $75,000 for single filers, and it disappears entirely at $175,000. Under Sequence B, the retiree's gross income of roughly $70,000 keeps her just below that threshold, preserving much of the deduction and pushing her effective tax rate even lower. Under Sequence A, heavy 401(k) withdrawals later in retirement push income well past $75,000 in many years, eroding that benefit entirely.

Why the brokerage stays parked

The $200,000 taxable account is the most valuable inheritance vehicle she owns, because of the step-up in cost basis at death. Heirs receive a basis reset to the date-of-death value, eliminating any embedded gains from federal tax. Spending it first to let the 401(k) keep compounding tax-deferred forfeits that step-up while guaranteeing a larger taxable RMD pile later. The arithmetic works against the conventional sequence in two ways at once: it shrinks the best inheritance asset while inflating the worst income-tax liability.

The IRMAA guardrail

Once Social Security begins, MAGI drives Medicare premiums. The first IRMAA threshold for a single filer in 2026 sits at $109,000. Crossing it by a single dollar triggers an extra $81.20 per month on Part B and $14.50 per month on Part D, a combined annual surcharge of roughly $1,148, applied against income reported two years prior under the standard lookback. Higher tiers are steeper: total Part B premiums can reach $689.90 per month at the top bracket. Sequence B's $40,000 401(k) draw plus $30,000 in Social Security keeps her well below that $109,000 line. A heavier Roth conversion during the same window would not.

Why the math is friendlier in 2026

Bracket adjustments, the higher standard deduction, and the expanded 12% bracket room all favor early drawdown this year. The One Big Beautiful Bill Act permanently locked in the current seven-bracket structure, eliminating the previously scheduled reversion to higher pre-TCJA rates. On the rate front, the Federal Reserve held its federal funds target range at 3.50% to 3.75% at the June 17, 2026 FOMC meeting, the first chaired by Kevin Warsh after succeeding Jerome Powell. That was the fourth consecutive hold at that level, yet the tone shifted markedly: the Fed removed all prior language suggesting an easing bias, and the dot plot moved to show nine of 18 participating officials expecting rates to end 2026 above the current range, with the median forecast rising to 3.8%. Markets subsequently priced in a meaningful chance of a rate hike before year-end rather than the cuts many expected at the start of 2026. The 10-year Treasury yield was running near 4.4% in late June 2026. Elevated rates do mean foregone investment growth in the 401(k) during the early drawdown window, but after netting out the tax savings from bracket smoothing, the case for Sequence B holds easily.

The hawkish pivot at the June meeting was partly driven by an energy-price spike tied to the Iran conflict. Consumer prices rose 4.2% year over year in May 2026, though core CPI, which strips out food and energy, came in at 2.9%. If energy prices recede, Fed officials may find room to hold steady rather than hike. Retirees using Sequence B benefit from the strategy regardless of the rate path, since the tax math does not depend on the Fed's next move.

Three actions worth taking this month

1. Calculate the dollar ceiling of the 12% bracket using the $18,150 standard deduction available to a single filer aged 65 or older in 2026. The 12% bracket tops out at approximately $50,400 of taxable income for single filers, which translates to roughly $68,550 in gross income before the standard deduction applies. That figure is the annual pre-RMD 401(k) withdrawal target. Withdraw to fill it, no more.
2. Project the first year Social Security and RMDs overlap. Every pre-RMD year between now and that date is the cheapest window available to convert or liquidate tax-deferred dollars at 12%. Skipping those years is the expensive choice.
3. Run projected MAGI against both the $109,000 IRMAA threshold and the $75,000 phase-out floor for the $6,000 senior deduction. If a planned 401(k) draw or Roth conversion lands within $5,000 of the IRMAA line, the two-year Medicare surcharge often eats the marginal tax savings. Reference IRS Publication 590-B for RMD divisors and CMS.gov for current IRMAA tiers.

Editor's note: This article was updated to add context from the June 17, 2026 FOMC meeting, including the dot-plot detail that nine of 18 participating officials projected the federal funds rate ending 2026 above its current 3.50% to 3.75% range (with the median forecast shifting to 3.8%), and to note that May 2026 headline CPI ran at 4.2% year over year while core CPI came in at 2.9%, with the energy spike tied to the Iran conflict. A clarifying sentence on the brokerage account's dual disadvantage under Sequence A was also added.

Contact [email protected] for any questions or corrections.