Working Past 65 · Hub

Working Past 65 in Ohio: Should You Enroll or Delay?

If your employer has 20 or more employees, you can usually delay Part B without a late-enrollment penalty for as long as your group health coverage stays active. If your employer has fewer than 20 employees, Medicare is generally your primary insurance and you should enroll on time at 65. The moment you enroll in any part of Medicare — including premium-free Part A — you must stop all HSA contributions. COBRA does not count as active employer coverage for Medicare purposes.

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About 40% of Ohioans age 65–69 are still working, often by choice and often at jobs with group health coverage. The federal rules that govern how Medicare interacts with employer coverage are easy to get wrong — and the penalties for getting them wrong follow you for life.

This page is the hub. The deep dives below cover the specific situations: HSA contributions, employer coordination, the Part B Special Enrollment Period, Part D creditable coverage, what to do if your spouse is on your employer plan, and how the timing changes when you retire at 66, 67, 68, or 70.

Why the 20-employee threshold matters more than anything else

Federal law says Medicare Secondary Payer (MSP) rules apply to employer plans with 20 or more employees. In plain English: at companies of that size, the employer plan pays first and Medicare pays second. Because your employer plan is primary, you can delay Part B without penalty until that coverage ends.

At companies under 20 employees, MSP rules flip. Medicare is primary and the employer plan is secondary. If you don't enroll in Part B at 65, the employer plan often won't pay the share that Medicare would have paid — leaving you exposed for 80% of your medical bills. Enroll on time.

The employer size is measured by total employee count, not by how many are in your group plan. Multi-employer plans (like union plans) have separate rules.

Self-employed in Ohio?

If you're self-employed and you carry your own health insurance through the Affordable Care Act marketplace (the Ohio exchange uses healthcare.gov), that's not employer coverage — it's individual coverage. You should enroll in Medicare at 65 unless you have a specific reason not to. ACA premium tax credits also stop when you enroll in any part of Medicare.

HSA contributions and Medicare don't mix

If you contribute to a Health Savings Account, this is the single most expensive mistake people make. The month you enroll in any part of Medicare, you must stop contributing to the HSA. That includes premium-free Part A.

Worse: when you eventually enroll in Part A, your enrollment is backdated up to 6 months (but not before age 65). Any HSA contributions you made in that retroactive window are considered "excess contributions" subject to a 6% IRS excise tax for every year they stay in the account.

Practical rule: stop HSA contributions at least 6 months before you actually file for Medicare or Social Security. If you've been collecting Social Security before 65, you're auto-enrolled in Part A and can't decline it — so HSA contributions had to stop already.

You can still spend HSA dollars on Medicare premiums, deductibles, copays, and almost any medical expense — including Medigap once you turn 65 (but the IRS doesn't allow Medigap before 65, and never allows Part D premium reimbursement from an HSA established by anyone other than yourself).

COBRA does not count as active employer coverage

If you leave a job at 65+ and elect COBRA, your COBRA period does not protect you from Medicare's late-enrollment penalty. The Special Enrollment Period to sign up for Part B starts the day you leave employment — not the day COBRA ends.

This catches Ohioans every year. They retire from a manufacturing job in Toledo, elect COBRA for 18 months, then try to enroll in Medicare and discover they owe a permanent 18% Part B penalty.

If you've left active employment, enroll in Part B immediately even if you also have COBRA. You can keep COBRA as secondary coverage for the duration if you want.

Your 8-month Part B Special Enrollment Period

When your active employer coverage ends — or when you stop working — you have 8 months to enroll in Part B without penalty. SSA needs two forms to use this SEP:

  • CMS-40B — Application for Enrollment in Medicare Part B
  • CMS-L564 — Request for Employment Information, signed by your former employer (proves you had group coverage based on current employment)

File these together. SSA may otherwise process your enrollment as a General Enrollment Period filing and stick you with the late penalty.

Worried about getting your CMS-L564?A licensed Ohio agent can walk you through both forms and time the handoff between employer coverage and Medicare.
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Part D creditable coverage — the easy one to forget

Your employer drug coverage may or may not be "creditable" — meaning it's expected to pay, on average, at least as much as standard Medicare Part D would. Your employer is required to send you a Notice of Creditable Coverage every year before October 15. Keep it.

As long as your coverage was creditable, you have a 2-month Special Enrollment Period to enroll in Part D when employer drug coverage ends — and no Part D late-enrollment penalty. Miss that 2-month window and you'll owe the penalty: 1% of the national base premium (about $0.39/month in 2026) for every month you went without creditable coverage. The penalty is permanent.

Note that this 2-month Part D window is much shorter than the 8-month Part B window. Don't conflate them.

Retiring at 66, 67, 68, or 70

Each year you delay retirement, the math shifts. The Part B premium goes up. Your Social Security check (if you wait past Full Retirement Age) goes up by 8% per year through age 70. Your HSA contributions add up. Your employer plan may have a Medicare-eligible carve-out where premiums drop or coverage shrinks at 65.

The right retirement age for you depends on your Full Retirement Age (FRA — 66 to 67 depending on your birth year), the quality of your employer plan, whether your spouse is also covered, and your tax situation. For most Ohioans we work with, retiring between 65 and 70 means navigating one transition — the employer-to-Medicare handoff — and getting it right matters more than the exact age.

Common questions

Do I have to enroll in Medicare at 65 if I'm still working?
Not necessarily. At an employer with 20 or more employees, you can usually delay Part B without penalty. At an employer with fewer than 20 employees, you should enroll on time because Medicare becomes your primary payer.
Can I keep contributing to my HSA after I enroll in Medicare?
No. The month you enroll in any part of Medicare, including premium-free Part A, you must stop contributing to your HSA. You can still spend down the existing balance.
Does COBRA delay my Medicare deadline?
No. COBRA is not active employer coverage for Medicare purposes. Your Special Enrollment Period to enroll in Part B starts when you leave employment, not when COBRA ends.
What happens to my HSA when I retire?
The balance stays yours. You can use HSA dollars for Medicare Part A, B, and D premiums (but not Medigap), and for most medical expenses tax-free. After age 65, non-medical withdrawals are taxed at your ordinary rate with no penalty.
Should I take Part A at 65 even if I'm delaying Part B?
Maybe not. Part A is premium-free for most people, but enrolling in it stops HSA contributions and may interact poorly with your employer plan. If you're getting Social Security, you'll be auto-enrolled in Part A whether you want it or not — only filing to defer Social Security keeps Part A delayed.
My spouse is on my employer health plan. Does she need Medicare at 65?
It depends. If she's 65+ and you're still working with 20+ employee coverage, she can delay Part B too — but her timeline and paperwork are separate from yours. Her Initial Enrollment Period, Medigap Open Enrollment Period, and SEP rules all run on her own clock.
HSAs and Medicare: the 6-month Part A lookbackWhy HSA contributors must delay Medicare and Social Security to keep contributing.Medicare and employer plans: the 20-employee ruleWhether your employer GHP is primary or secondary depends entirely on employer size.Part B SEP and Form CMS-L564The 8-month window after employer coverage ends, and the form your HR completes.Part D creditable coverage and the 2-month SEPDrug coverage rules when transitioning from employer to Medicare.Spouse on employer plan: Medicare for couplesWhen you're 65+ but on your working spouse's plan — or vice versa.Retiring at 66, 67, 68, or 70: timing for OhioMedicare at 65, Social Security at FRA or 70, and how the timing decisions interact.