The Tax Time Bomb: How RMDs Can Shrink a Big IRA in Retirement
The danger is not that you saved too much. It is that too much of your wealth may be trapped behind the same future tax bill.
By Seth Liskey, CFP®, CEPA | CEO, Middlebrook Wealth
Most successful savers spend thirty or forty years hearing the same advice: put money into the 401(k), take the deduction, capture the employer match, and let the account compound. That is usually good advice.
But a tax deduction is not tax forgiveness. It is a postponement.
The balance on a traditional 401(k) or IRA can look wonderfully reassuring. Yet withdrawals are generally taxed as ordinary income. You own the account, but the number on the statement is not the same as the amount you can spend.
That is not automatically a problem. The problem begins when nearly all your retirement wealth has the same tax treatment and the calendar eventually takes away your ability to choose when to recognize the income.
The RMD Forced-Income Problem
Traditional retirement accounts eventually become required income. Under current law, the applicable RMD age is generally 73 for people born from 1951 through 1959 and 75 for those born in 1960 or later. Those withdrawals arrive whether you need the cash or not.
By then, many retirees already have Social Security, a pension, dividends, interest, or rental income. The required distribution lands on top. More income can make a larger portion of Social Security taxable, push the household into a higher marginal bracket, and raise Medicare Part B and Part D premiums.
Medicare adds a particularly unintuitive wrinkle: its income-related surcharges generally use tax-return information from two years earlier. A conversion or large IRA withdrawal that looks manageable today can show up later as a higher healthcare premium.
A Simplified Example
Consider a hypothetical couple retiring in their early sixties with $3 million of investable assets. They have done many things right. The issue is that $2.5 million sits in traditional retirement accounts, while only $500,000 is in taxable savings and cash.
If the $2.5 million pre-tax balance earned a hypothetical 5% annually for thirteen years—with no withdrawals or Roth conversions—it would grow to roughly $4.7 million. Using today’s IRS Uniform Lifetime Table, an age-75 first-year RMD on a balance of that size would be about $192,000.
Illustration only: This is not a forecast. Actual returns, spending, distributions, tax law, Medicare thresholds, and the age at which distributions begin may differ. The example simply shows how a large pre-tax balance can turn into a large stream of forced taxable income.
Add Social Security and other household income, and the couple may have far less control over their tax return than they expected. They did not fail to save. They failed to build enough tax diversification before the decisions became mandatory.
The Tax Bill Is Bigger Than the Tax Bracket
Social Security
Depending on combined income, up to 85% of Social Security benefits may be included in taxable income. An IRA withdrawal can therefore make more income appear on the return: the withdrawal itself, plus a larger taxable share of Social Security.
Medicare Premiums
For 2026, the first income-related Medicare premium tier begins above $109,000 for an individual or $218,000 for a married couple filing jointly. Those figures change over time, but the planning lesson does not: crossing a threshold by a small amount can raise Part B and Part D costs for an entire year.
The Surviving-Spouse Squeeze
After one spouse dies, one Social Security benefit usually disappears, but the surviving spouse may still have much of the same pension income and a consolidated IRA. The household can move from joint tax brackets to narrower single brackets while many expenses remain. Income can fall and the marginal tax rate can still rise.
The Next Generation
Many non-spouse beneficiaries generally must empty an inherited IRA by the end of the tenth year after the owner’s death. Those distributions may land during the beneficiaries’ peak earning years. A tax-deferred inheritance can be valuable, but it is not the same as an equally sized tax-free inheritance.
Why the 5-to-15 Window Matters
The most valuable tax-planning years often begin before retirement and extend well into it. I call this the 5-to-15 Window: the five years before retirement and the fifteen years after.
During that window, earned income may decline before RMDs begin. Social Security may not have started yet. A business sale, pension election, charitable plan, and Medicare enrollment may still be coordinated rather than merely reacted to.
Those years can create room for partial Roth conversions, deliberate IRA withdrawals, capital-gain harvesting, charitable giving, or changes in asset location. The word partial matters. The goal is not to convert everything or to pay the least tax this year. The goal is to pay the lowest reasonable lifetime tax while preserving flexibility.
Six Ways to Defuse the Problem
Build more than one tax bucket. A mix of traditional, Roth, taxable, and, when eligible, Health Savings Account assets creates more ways to fund spending without making every dollar appear as ordinary income.
Set an annual tax budget. Each year, estimate how much income can be recognized intentionally before crossing the tax, Medicare, healthcare-subsidy, or capital-gain thresholds that matter to the household.
Coordinate Social Security with the tax plan. Delaying Social Security may create additional years for conversions and can increase the eventual benefit, but it should be evaluated alongside longevity, cash flow, spousal benefits, and the rest of the plan. When Should I Take My Social Security Benefits?
Use charitable dollars strategically. After age 70½, a qualified charitable distribution can send IRA dollars directly to an eligible charity and may satisfy part or all of an RMD without adding the distribution to taxable income.
Model the survivor and heir outcome. A plan that works for a married couple can change quickly when the tax return becomes single or when children must distribute an inherited account over a shorter period.
Get your advisor and your CPA in the same conversation. Most of the strategies on this list only work when the person managing your money and the person filing your taxes are working from the same plan. That means sitting down together before the end of the year, not after the return is filed, to decide how much income to recognize and why. This coordination is the role of the financial quarterback, and the gap between those silos is where the money is lost.
When a Roth Conversion Is Not the Answer
Roth conversions are powerful, but they are not automatically good. Converting at a higher rate than the household is likely to pay later can destroy value. A conversion can also trigger Medicare surcharges, reduce Affordable Care Act subsidies before age 65, increase the tax rate on capital gains, or create a cash-flow problem if the taxes cannot be paid from outside the IRA.
Charitably inclined retirees may also prefer to preserve some traditional IRA dollars for future qualified charitable distributions. State taxes, estate plans, beneficiary tax rates, and expected spending all matter. There is no universal conversion age and no universal conversion amount.
The right question is not, “Should I convert my IRA?” It is, “How much income should I recognize this year, from which account, and what future problem does that decision solve?”
The Real Goal Is Choice
Retirement tax planning is not about defeating the IRS. It is about making taxes one of the variables you manage deliberately instead of an expense you discover after the best options have expired.
A large IRA is a sign of discipline and decades of good decisions. It should also be the beginning of a distribution strategy, not the end of the planning conversation.
If retirement is within the next five years, or if you have already retired and RMDs have not yet begun, this is the time to map your current tax buckets, project future required income, and decide which years may offer the most valuable planning opportunities.
You do not have to work through it alone. Our team is here to help you look at your full picture, coordinate with your CPA, and build a strategy designed for your specific situation.
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