Turning 65, Medicare & Your HSA: Case Work From a Texas Client

This is a real case work story (with identifying details removed), not legal or tax advice. HSA and Medicare rules are technical and can change. Always confirm your own facts with IRS guidance (including Publication 969) and a qualified professional before acting.

The question that started it: “Will I get penalized if I retire?”

Here’s what my client laid out on our first call:

• He will turn 65 in January 2026.
• He’s covered by a qualifying High Deductible Health Plan (HDHP) with an HSA.
• His employer plans to contribute $2,000 in January and $2,000 in March 2026 to his HSA.
• He wants to retire sometime in 2026 and start Medicare.

His concern: if he retires and enrolls in Medicare, would those 2026 HSA contributions trigger penalties? And could he still use the HSA money during 2026 without a problem?

Step 1 – Go back to the actual HSA–Medicare rule

I don’t guess on this stuff; I go straight back to the IRS language. For HSAs, the key piece is in IRS Publication 969 under the “Enrolled in Medicare” section. Once you enroll in Medicare:

• You can’t be an eligible individual for HSA contributions anymore, and
• Beginning with the first month you are enrolled in Medicare, your HSA contribution limit is $0, including periods of retroactive Medicare coverage.

That means:

• Any contributions made for months you’re actually covered by Medicare (including coverage that is backdated) are treated as excess contributions.
• Excess HSA contributions are generally subject to a 6% excise tax each year until they’re corrected, unless you withdraw them (and the earnings on them) properly by your tax return due date.

At the same time, Pub. 969 and related guidance make it clear that if you’re no longer eligible to contribute, you can still use the existing HSA balance for qualified medical expenses, including many Medicare premiums.

Step 2 – I walked him through how HSA eligibility ends

On our follow-up call, I broke it down in plain English:

• To be HSA-eligible, you need to have an HDHP, no disqualifying other coverage, and you must not be enrolled in Medicare.
• As soon as you enroll in Medicare, you stop being eligible to make HSA contributions for that month and any later months.
• If your Medicare enrollment is made effective retroactively (for example, you enroll later in the year but Part A is backdated up to six months), the HSA rule looks backward and treats contributions for those months as excess.

I told him: “Once you actually enroll in Medicare, you’re done contributing. From that first month of Medicare coverage, your HSA contribution limit is literally $0. But your HSA balance doesn’t vanish — it just turns into a tax-favored bucket you can spend from.”

Step 3 – Mapping his timeline: turning 65, employer contributions, and retirement

With the rules on the table, we put his facts on a simple mental timeline:

• January 2026: Turns 65. Employer scheduled to contribute $2,000 to HSA.
• March 2026: Another $2,000 scheduled from employer.
• Sometime in 2026: He wants to retire and start Medicare.

The core planning questions became:

• In which month will Medicare coverage actually start?
• Will there be any retroactive Medicare coverage that reaches back over those employer contributions?
• Do we need to stop future contributions or clean up excess ones if the timing doesn’t line up perfectly?

I explained that there are really two levers:

1. Control future contributions. Once he chooses a Medicare start date, he and his employer would need to stop HSA contributions for any month that will be covered by Medicare (including any months pulled in by retroactive coverage).
2. Fix any excess contributions. If contributions are already made for months when he was actually covered by Medicare, we can treat those as excess and have them returned (with earnings) by the tax filing deadline to avoid the 6% excise tax.

We didn’t try to “game” it; we just lined up his planned retirement date and the Medicare rules so there would either:

• Be no contributions during Medicare-covered months, or
• Be a clean plan to withdraw any excess contributions that get caught by the retroactive coverage rule.

Step 4 – Reassuring him about using his HSA after Medicare

His second big fear was that once he touched Medicare, his HSA would somehow be “penalized” or “locked.”

I clarified:

• Once you’re on Medicare, the rule changes your ability to contribute, not your ability to spend.
• You can generally still use the HSA balance for qualified medical expenses for yourself, your spouse, and your dependents.
• That includes things like:
  • Medicare Part B premiums,
  • Medicare Part D (drug plan) premiums, and
  • Medicare Advantage (Part C) premiums,
  as well as copays, deductibles, and many other out-of-pocket costs.
• One big limitation to know about: HSA funds can’t be used for Medigap (supplement) premiums as a qualified expense under current rules.

So the answer to his “Can I still use my HSA in 2026?” question was a calm yes, as long as we respected the contribution rules.

Step 5 – The actual solution we landed on

After walking through the law and his timing, here’s how we resolved it together:

• We confirmed from IRS Publication 969 that:
  • He can’t make or receive HSA contributions for any month he’s enrolled in Medicare, and
  • Any contributions made during a period of retroactive Medicare coverage would be treated as excess and can trigger a 6% excise tax if not fixed.
• We agreed that once he picks his retirement and Medicare start date, we’ll:
  • Coordinate with his employer to stop HSA contributions for any months that would be Medicare-covered, and
  • Run a month-by-month HSA contribution limit (using the Form 8889 limitation rules) to confirm whether any 2026 contributions need to be returned as excess.
• We clarified in writing that:
  • He can keep and use his HSA balance after he retires,
  • He can use it for many Medicare-related expenses and other qualified medical costs,
  • And the main penalty risk is from contributing when he’s no longer HSA-eligible, not from spending the funds correctly.

By the end, his question “Will I be penalized for retiring?” turned into a much more precise, calmer understanding:

• “I need to stop HSA contributions once Medicare coverage starts (including any retroactive window), or get any ‘extra’ contributions refunded properly.”
• “I’m free to keep using my HSA balance for qualified medical expenses, including Medicare premiums where allowed.”

That’s the real win in case work like this — not just answering the question, but giving the client a clear roadmap so they don’t have to guess in the dark.