The Healthcare Mistake MANY Early Retirees Make With a $2M 401(k)

If you are retiring before 65 and trying to qualify for ACA marketplace health insurance subsidies, there is a costly mistake that most people miss entirely. Keeping your reported income low enough to maximize your subsidy feels like the responsible move, and in the moment it usually is a real savings on your monthly premium.

What gets overlooked is what that low-income strategy costs you on the other side of the ledger. For households with large 401(k) and IRA balances, the years between retiring and turning 65 are often the best window you will ever have to complete Roth conversions at a manageable tax rate. Keeping income artificially low to protect a subsidy can mean skipping that window almost entirely.

Here is how that tradeoff plays out, and who should be paying the closest attention to it.

Key takeaways:

• Keeping income low for ACA subsidies before 65 can mean giving up one of your best years for Roth conversions.

• Skipping conversions during this window often leads to a larger pretax balance, and larger RMDs, later on.

• Larger future RMDs increase the odds of higher tax brackets and IRMAA surcharges on Medicare premiums once you turn 65.

• This tradeoff matters most for pre-retirees ages 55 to 65 and retirees in their first 10 years with $1 million or more across 401(k)s, IRAs, and brokerage accounts.

• The right answer is not to ignore ACA subsidies, it is to weigh the near-term premium savings against the longer-term tax cost before deciding.

Why the Pre-65 Years Are a Prime Roth Conversion Window

Once you stop earning a full salary, your reported income often drops for the first time in years, which is exactly the condition that makes Roth conversions efficient: you can convert a deliberate amount of pretax savings and have it taxed at a comparatively low rate. For households with $1 million or more sitting in 401(k)s and IRAs, this stretch of lower income before Medicare eligibility at 65 is frequently the most efficient conversion window in the entire retirement timeline.

The tradeoff is that converting adds to your reported taxable income for the year, which is the same number that determines your ACA subsidy eligibility. A large conversion can reduce or eliminate a subsidy you would otherwise receive, which is why many early retirees choose to keep conversions small or skip them to protect the subsidy instead.

The Cost of Choosing Subsidies Over Conversions

A smaller subsidy is a visible, immediate cost. A missed conversion window is a delayed, less visible cost, which is exactly why it gets missed. Pretax balances left unconverted during your pre-65 years continue growing, and that larger balance becomes the base your RMDs are calculated from once you reach RMD age. A bigger pretax balance at that point generally means bigger RMDs, and bigger RMDs mean more taxable income landing in years you did not choose.

That additional income at RMD age can push you into a higher bracket than the one you were protecting during your ACA years, and it can also trigger IRMAA surcharges on your Medicare Part B and Part D premiums, an ongoing cost that a one-time subsidy savings does not offset. For a household with a $2 million 401(k), the difference between converting steadily in the pre-65 years and skipping conversions to protect a subsidy can be a meaningfully different tax bill for the rest of retirement.

Who Should Be Weighing This Tradeoff Now

This decision matters most for pre-retirees ages 55 to 65, retirees already in their first ten years of retirement, married couples coordinating two income pictures, and any household with $1 million or more combined across 401(k)s, IRAs, and brokerage accounts. For these households, the ACA subsidy and the Roth conversion window are not separate decisions, they are the same decision looked at from two different angles.

The goal is not to abandon ACA subsidies altogether, it is to run the comparison deliberately: what does a given subsidy save this year, versus what does a given conversion amount save in reduced future RMDs and IRMAA exposure. That comparison, done year by year, is a core part of how we build the pre-65 years into a client's Retire Ready Roadmap™.

Why does keeping my income low for ACA subsidies affect my Roth conversions?

Because ACA subsidy eligibility and the taxable income created by a Roth conversion are calculated from the same number, a larger conversion can reduce or eliminate the subsidy you would otherwise receive in that year.

Who is most affected by this healthcare and tax tradeoff?

Pre-retirees ages 55 to 65, retirees in their first 10 years, married couples, and households with $1 million or more across 401(k)s, IRAs, and brokerage accounts are the ones most likely to face this decision directly.

Does skipping conversions to protect a subsidy actually cost more later?

It can. A larger unconverted pretax balance generally produces larger RMDs once you reach RMD age, which can push you into a higher tax bracket and trigger IRMAA surcharges on Medicare premiums, both of which are ongoing costs.

Should I stop trying to qualify for ACA subsidies before 65?

Not necessarily. The goal is to weigh the subsidy savings in a given year against the longer-term cost of a delayed Roth conversion, rather than defaulting to the lowest possible reported income without running that comparison.