Why a 65-Year-Old With $1.8 Million Is Spending Her 401(k) Before Claiming Social Security at 70

A 65-year-old single woman walks into retirement with $1.8 million in a traditional 401(k), $250,000 in a taxable brokerage, and $100,000 in cash. She wants to spend $80,000 a year. Conventional wisdom says to file at full retirement age 67 and let the 401(k) keep compounding. A smarter sequence flips that logic entirely: draw down the 401(k) and brokerage from ages 65 to 70, and let the Social Security check grow to its maximum before the first dollar arrives.

Why the bridge years are worth more than the deferral

Her benefit at full retirement age would be $36,000 a year. Waiting until 70 turns that into $44,640, courtesy of the delayed retirement credit of 8% per year past FRA. Those credits accumulate at two-thirds of 1% per month and stop accruing entirely at age 70, so filing even one month past that birthday forfeits income with no path to recovery. Run the higher check out to age 90 and the extra income totals $172,800 in nominal dollars, before any cost-of-living adjustment compounds on the larger base.

The inflation backdrop makes that larger base especially valuable right now. The consumer price index posted a 4.2% annual rate in May 2026, its highest reading since April 2023, before easing to 3.4% in August. The September 2026 CPI report, due October 15, is forecast to come in near 3.6% as energy prices remain elevated. An inflation-protected benefit locked in at its maximum carries real purchasing-power advantages that a smaller benefit claimed earlier cannot replicate.

The five-year drawdown math

Five years of $80,000 spending equals $400,000. Splitting withdrawals roughly evenly between the 401(k) and the brokerage keeps her inside the lowest two federal brackets throughout the bridge period. In 2026, a single filer aged 65 or older claims a base standard deduction of $16,100 plus an additional $2,050 senior add-on, for a combined $18,150 shielded from tax before a dollar of 401(k) income is counted. The One Big Beautiful Bill Act added a separate temporary $6,000 senior bonus deduction on top of that for single filers aged 65 and older, available for tax years 2025 through 2028. The bonus begins phasing out at $75,000 MAGI at a rate of 6% of income above that threshold, and disappears entirely at $175,000. For a retiree drawing modest bridge income, the full $6,000 is almost certainly in reach.

Taking $40,000 from the 401(k) and subtracting the $18,150 combined base deduction leaves roughly $21,850 of taxable income. That sits comfortably inside the 12% bracket, which runs to $48,475 for single filers in 2026, and produces roughly $2,600 in federal tax per year, or about $13,000 across the five-year bridge. The math is lean by design.

The brokerage half is even cheaper to access. Long-term capital gains stacked on top of that modest ordinary income largely fall inside the 0% capital gains rate, which applies to taxable income up to $49,450 for single filers in 2026. Any unrealized losses in the portfolio can be harvested to offset future gains, compressing the tax bill further.

The RMD and Social Security tax cascade she avoids

Draining roughly $200,000 from the 401(k) during the gap years reduces her year-one required minimum distribution at age 73 by about $7,800. That reduction is meaningful on its own, but the bigger prize is the provisional-income math. Once Social Security starts, single filers see up to 50% of benefits become taxable above $25,000 of provisional income, and up to 85% above $34,000. Those thresholds have not been indexed for inflation since 1984, which means more retirees collide with them every year. The One Big Beautiful Bill Act introduced significant new deductions for seniors but left the underlying provisional-income formula entirely intact, keeping this cascade very much in play for higher-income retirees.

A larger Social Security check at 70 displaces the 401(k) withdrawals that would otherwise push her over those thresholds. A retiree in the 22% bracket who simultaneously triggers 85% Social Security taxation and an IRMAA Medicare surcharge can face an effective marginal rate near 40% on the next dollar pulled from the 401(k). The bridge strategy is designed to keep her well clear of that trap.

The interest rate environment adds another tailwind. At its September 16, 2026 meeting, the Federal Reserve voted 12 to 0 to raise its benchmark federal funds rate by a quarter point to 3.75% to 4%, its first rate hike in more than three years. The September dot plot showed the median official projecting one additional 25-basis-point hike before year-end, which would bring the rate to 4.00% to 4.25%. That median projection of 4.1% rose from 3.8% in the June dot plot, and a small number of participants penciled in a second additional hike. The next FOMC decision is scheduled for October 27 to 28. At current rate levels, cash and short-duration bonds inside the 401(k) still generate a real return, so the bridge period is not quietly eroding purchasing power while it does its work.

What to do in the next 30 days

1. Map the bracket fill. Pull only enough from the 401(k) each year to bring taxable income to the top of the 12% bracket. With the 2026 single 12% bracket ending at $48,475, that leaves room for small bracket-filling Roth conversions inside the same window, shrinking future RMDs further.
2. Run the brokerage first on appreciated lots with offsetting losers. Harvest losses while drawing it down so that capital gains stay inside the 0% rate and never collide with the eventual Social Security check.
3. File for Social Security the month you turn 70. Delayed retirement credits stop accruing at 70. Waiting even a single extra month past that birthday is pure forfeited income.

The arithmetic favors the reverse sequence. Spend the tax-deferred dollars while the standard deduction and age-related deductions are absorbing them, and let the inflation-protected government annuity grow to its largest possible base before the first check ever arrives.

Editor’s note: This pass corrected the September 2026 dot plot characterization to reflect the confirmed median year-end rate projection of 4.1% (one additional hike to 4.00%-4.25%), up from a June median of 3.8%, replacing an imprecise range that overstated the upper end. It also added the September 2026 CPI forecast of approximately 3.6% as updated inflation context, and sharpened the senior deduction phase-out language to specify the 6% reduction rate and the $175,000 complete elimination threshold for single filers.

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