The $3 Million 401(k) Problem High Earners Don’t See Coming

You spent 30 years building a $3 million 401(k), and at 73 the IRS will start dismantling it on its own schedule. The forced withdrawals are called required minimum distributions, and at that balance they create a tax collision that most high earners never modeled during the accumulation phase.

The Size of the Forced Withdrawal

The IRS calculates your RMD by dividing your prior year-end balance by a life expectancy factor from the Uniform Lifetime Table. At age 73, that factor is 26.5, so a $3 million balance generates a first-year RMD of roughly $113,000.

The portfolio is likely still growing. Assuming 6% annual growth, the balance climbs to roughly $3.18 million the following year. But the distribution factor also shrinks: at age 74 it is 25.5, pulling out approximately $124,700. At age 75, with a factor of 24.6 applied to a roughly $3.24 million balance, the RMD reaches about $131,600. The withdrawals accelerate faster than most people expect, even as the portfolio holds its value.

Where the Tax Torpedo Hits

The real damage comes from what that $113,000 RMD lands on top of. Add a modest Social Security benefit and a small pension, and a single filer’s income can easily cross $170,000. That falls within the 24% federal bracket, which in 2026 (after adjustments under the One Big Beautiful Bill Act) runs up to $201,775 for single filers. But the visible bracket rate is only the beginning.

Up to 85% of Social Security benefits become taxable once combined income exceeds IRS thresholds. On top of that, IRMAA surcharges activate. IRMAA (Income-Related Monthly Adjustment Amount) is Medicare’s income-based premium surcharge, and it uses a two-year lookback: your 2024 tax return determines your 2026 premiums.

For 2026, IRMAA surcharges begin at $109,000 for single filers and $218,000 for married filing jointly. A married couple whose combined income hits Tier 3 (between $342,001 and $410,000) adds $9,240 per year in combined Part B and Part D surcharges. Cross into Tier 4 (above $410,000) and the annual penalty for the couple jumps to $12,710.

Between the 24% bracket, the Social Security “tax on a tax,” and the IRMAA cliff, a retiree can face an effective marginal rate near 40% on those final RMD dollars. The 401(k) deduction that saved 37 cents on the dollar during peak earning years can cost significantly more on the way out.

The Window That Closes at 73

SECURE 2.0 pushed the RMD start age to 73, with a further increase to 75 for those born in 1960 or later, effective 2033. That delay is valuable only if you use the gap years between retirement and RMD age strategically.

If you retire at 65 or 67, you have six to eight years where taxable income is lower than it has been in decades. Traditional 401(k) balances sit untouched, growing tax-deferred. This is the optimal window for Roth conversions: moving money from the traditional account into a Roth, paying tax now at a lower rate, and permanently removing that balance from future RMD calculations.

Roth 401(k)s carry no RMDs during the owner’s lifetime under SECURE 2.0, a rule effective beginning in 2024. Every dollar converted before age 73 is a dollar that will never generate a forced taxable event. On a $3 million balance, converting $200,000 per year for six years during the gap eliminates roughly $1.2 million from the RMD base, reducing the age-73 RMD by more than $45,000 annually at the initial factor.

Retirees who are charitably inclined have an additional lever. A qualified charitable distribution (QCD) allows an IRA owner who is 70.5 or older to transfer funds directly to a charity, satisfying all or part of an RMD without the distribution ever appearing as taxable income. The 2026 QCD limit is $111,000 per person, up from $108,000 in 2025, making it a meaningful offset for those with philanthropic goals.

Three Steps Worth Taking Now

1. Calculate your projected age-73 RMD using the IRS Uniform Lifetime Table and your current balance grown at a conservative rate. Layer in Social Security, any pension income, and capital gains distributions to see which IRMAA tier you will land in. The 2026 standard Part B premium is $202.90 per month; the surcharge tiers above that can add hundreds more per person per month, and they are calculated from income two years prior, not the year you pay them.
2. Model Roth conversions in the gap years between retirement and age 73. The goal is to fill your current bracket without crossing into the next IRMAA tier. Converting to the top of the 24% bracket (up to $201,775 for single filers in 2026) while staying below the first IRMAA threshold is the most efficient conversion corridor for most people in this balance range.
3. If your projected combined retirement income exceeds $218,000 for a married couple, the tax planning alone justifies a fee-only advisor. The IRMAA two-year lookback means an ill-timed income spike, such as a Roth conversion or a property sale, can trigger premium surcharges you must pay for 12 months. The SSA rarely grants appeals for one-time income gains, so getting the timing right is worth the cost of professional guidance.

Editor’s note: This article was updated to add the 2026 qualified charitable distribution limit of $111,000 as a tax-reduction strategy alongside Roth conversions, and to note that the 2026 federal tax brackets reflect adjustments made under the One Big Beautiful Bill Act.