A $900,000 401(k) at 73 Produces a $34,000 RMD That Quietly Lifts a Couple’s Medicare Premiums, and Here’s the Fix

A 73-year-old retiree in Cleveland posted on a personal-finance forum that her first required minimum distribution arrived without incident. Her tax software then flagged something she had not anticipated: both her and her husband’s Medicare Part B premiums were about to rise, and the trigger was a $34,000 line item she did not control.

Their situation is a familiar one. A $900,000 traditional 401(k), both spouses on Medicare, combined Social Security and a small pension sitting comfortably below the first IRMAA threshold. The RMD did not look alarming on its own. It was the combination that broke the seal. What makes the timing especially sharp in 2026 is that Medicare uses income from two years prior, meaning the 2024 tax year is what determines the 2026 premium bill, and the 2026 standard Part B premium jumped nearly 10% from 2025 levels, making every threshold crossing more expensive than it used to be.

How $900,000 Becomes a $34,000 Problem

The IRS Uniform Lifetime Table assigns a divisor of 26.5 at age 73. Divide $900,000 by 26.5 and the first-year RMD lands at roughly $33,962. Most people round that to $34,000 and move on, which is fair. The number itself does not look threatening.

The problem is what it does in combination with other income streams. That single distribution does three things at once. It enters federal taxable income as ordinary income. It counts toward the Social Security taxation formula, pushing up to 85% of combined benefits into the taxable column. And it lands in modified adjusted gross income, which Medicare uses, with that same two-year lookback, to set the following year’s Part B and Part D premiums.

The 2026 standard Part B premium is $202.90 per month, up $17.90 from the $185.00 rate in 2025. That 9.7% increase was one of the largest single-year jumps in years, and it means the IRMAA cliff now has a higher base to build on. For a married couple filing jointly with MAGI at or below $218,000, $202.90 is the bill. Cross $218,000 by even a dollar and the total monthly premium rises to $284.10 per spouse. Cross $274,000 and it climbs to $405.80. Part D adds a smaller surcharge on top of those figures: $14.50 per person at the first tier and $37.50 at the second.

The Math the RMD Does Quietly

Consider a couple with $52,000 in combined Social Security, a $48,000 pension, and $85,000 in dividends and interest from a taxable brokerage account. They sit at $185,000 MAGI, comfortably below the first cliff. Add the $34,000 RMD and the figure moves to roughly $219,000. They are one thousand dollars over the threshold.

That single dollar of overage triggers the full first-tier surcharge for both spouses simultaneously. The extra $81.20 per month for Part B, across two people over twelve months, works out to about $1,949 for the year. Add two Part D surcharges at $14.50 each and the household bill climbs to roughly $2,297. None of it phases in gradually. IRMAA is a cliff system: it applies in full at the first dollar of overage, which is what makes this trap so costly relative to the amount involved.

For a couple carrying a larger balance or higher dividend income, the math can push MAGI into the $274,000 to $342,000 range instead. At that tier, the Part B portion alone runs near $4,870 per year for the household, and Part D adds another $900. Add federal income tax on the RMD itself (the 22% joint bracket covers income from $100,800 to $211,400 in 2026) and the effective cost of that last $34,000 withdrawal climbs toward 27% before state tax enters the picture.

The Fix That Actually Works at 73

The cleanest tool for this couple is the Qualified Charitable Distribution. After rolling the 401(k) to a traditional IRA, each spouse can direct up to $111,000 of their RMD directly to a qualified public charity in 2026. That amount counts toward the RMD obligation but never enters MAGI. A targeted $10,000 QCD from the $34,000 requirement pulls combined income back under the $218,000 threshold and erases the IRMAA surcharge for both spouses entirely.

The QCD carries added force in 2026 because the One Big Beautiful Bill Act reshaped the landscape for itemized charitable deductions. Starting this year, donors who itemize can only deduct contributions that exceed a floor of 0.5% of their AGI, and taxpayers in the top 37% bracket face an additional cap limiting the tax benefit to 35 cents per dollar. QCDs sidestep both restrictions entirely. Because the QCD is an income exclusion rather than a deduction, it does not interact with itemized deduction limits at all. The strategy remains fully intact regardless of whether the couple itemizes.

Three steps make this concrete:

1. Run a draft 1040 in November using estimated dividends and the actual RMD amount. If MAGI lands within $10,000 of $218,000 or $274,000, the IRMAA math is in play and worth a call to the IRA custodian before December.
2. Direct the QCD from the IRA custodian to the charity before December 31. The check must travel from the IRA directly to the qualified charity. A reimbursement of a personal donation does not qualify, and a 401(k) cannot make a QCD directly, which is why the rollover step matters.
3. If a one-time event (loss of a pension, a spouse’s death, work stoppage) caused the income spike two years ago, file Form SSA-44. Social Security can reset the IRMAA tier for the current year without waiting for the two-year lookback to unwind on its own.

The threshold crossing is what drives the cost. A household with a $900,000 balance can almost always engineer income back under the line by reviewing the full picture of pensions, dividends, and Social Security before December, rather than discovering the surcharge notice in the mail after the year has already closed.

Editor’s note: This revision added context on the 9.7% Part B premium increase from 2025 ($185.00) to 2026 ($202.90) and clarified that the One Big Beautiful Bill Act’s new 0.5%-of-AGI floor on itemized charitable deductions does not affect QCDs, which operate as an income exclusion rather than a deduction.

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