The $1.5 Million Retirement Tax Trap Many Couples Miss

Here is a scenario that catches a lot of successful people off guard: a $1.5 million traditional 401(k) can push a retired couple into a higher tax bracket in retirement than they ever hit during their peak earning years.

Not because they spent recklessly, but because the IRS mandated it.

Why the Tax Math Shifts in Retirement

Once you reach age 73, the IRS requires you to withdraw a set percentage of your pre-tax retirement accounts each year, whether you need the money or not. On a $1.5 million balance that has continued compounding, those forced withdrawals could land a married couple squarely in the 22% or 24% bracket and keep them there for the rest of their lives.

The window to act is the gap between now and age 73. During that stretch, you can move pre-tax dollars into a Roth account, pay tax at today's rates, and potentially reduce the balance that will eventually be subject to RMDs. What remains in the Roth grows and is distributed tax-free.

The IRMAA Cliff You Need to Know

For a married couple filing jointly, Medicare IRMAA surcharges begin the moment income exceeds $218,000 (based on 2024 MAGI, as reported by CMS). The first tier adds $81.10 per month, per person, to Part B premiums, roughly $1,950 a year in additional Medicare costs triggered by a single year of over-converting.

Therefore, the target is not "convert as much as possible." The target is the bracket ceiling, managed carefully below the IRMAA threshold. For a couple in the 22% bracket, that could mean converting $50,000 to $100,000 per year while staying safely below that $218,000 threshold. Done consistently over a decade, the compounding effect on tax-free growth could be substantial.

It's Not Just About Tax Brackets

There are also downstream interactions worth understanding:

• Social Security taxation — higher income in retirement can cause up to 85% of your Social Security benefit to become taxable

• Capital gains rates — conversion income can push long-term capital gains into a higher rate tier

• Heir considerations — a Roth inherited by a non-spouse beneficiary still grows tax-free, while a traditional IRA forces distributions taxed at the heir's ordinary income rate

  
  

For married couples in particular, the stakes are elevated. If one spouse passes away, the survivor files as a single taxpayer, compressing into narrower brackets immediately and often facing a steep tax increase on the same income.

Why It Matters

If you're in your 50s or 60s with a large traditional 401(k) or IRA, you may have an important planning window ahead of you. The question is whether you are moving through it deliberately or letting it close by default.

You don't know what future tax rates will be, and Roth conversions aren't automatically the right answer.

But waiting until RMDs begin can mean giving up years when you had more control over your taxable income.

Retirement tax planning isn't about avoiding taxes. It's about having more control over when you pay them and potentially how much you pay.

 - Steve Balch, CFP®

Steve Balch, CFP®, is a financial advisor and financial planner in Bergen County, New Jersey, helping individuals and families in their 40s, 50s, and 60s build wealth and prepare for retirement. He provides comprehensive financial planning, retirement planning, investment management, and tax-aware financial strategies designed to coordinate income, investments, taxes, and long-term retirement goals. Steve helps clients throughout New Jersey and across the country make confident financial decisions so they can enjoy life today while building toward a secure retirement.

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When You’re Ready to Take the Next Step, Here’s How I Can Help You:

Work with me. If you would like to understand what a multi-year Roth conversion strategy could look like for your specific situation, including how it interacts with your other income sources, your tax bracket, and Medicare, I would be glad to walk through the numbers with you: click here to schedule a call with me.

Ask me a financial question. If there’s something you’ve been wondering about financially - taxes, investments, retirement, or anything else - send me a message on LinkedIn. I’m happy to discuss and help you find clarity.

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