Retirement creates a Medicare deadline
If you delayed Part B because you or your spouse had qualifying coverage based on current employment, you generally have an 8-month Special Enrollment Period after the employment or group health coverage ends, whichever happens first. But waiting eight months may leave you without the coverage you actually need.
Still working after 65? Employer size matters
Whether Medicare or your employer plan generally pays first can depend on the size and type of employer coverage. For many people age 65 or older, a group health plan from an employer with 20 or more employees generally pays first and Medicare pays second. With an employer that has fewer than 20 employees, Medicare generally pays first.
A smoother retirement sequence
- Ask your employer for the exact date your active employee health coverage ends.
- Plan your Part B effective date so you don't create a gap.
- Complete the Social Security enrollment process and proof of prior employer coverage when required.
- Confirm whether your prescription coverage has been creditable and keep the notice.
- Choose how you'll receive Medicare benefits and how prescriptions will be covered.
- Do not cancel existing coverage until replacement effective dates are confirmed.
Have an HSA? Plan ahead
Once you are enrolled in Medicare, you can no longer contribute to an HSA. If you enroll in premium-free Part A after age 65, Part A can generally be retroactive for up to six months, but not earlier than the first month you were eligible for Medicare.
Prescription coverage matters too
If you delayed Part D because you had employer prescription coverage, verify that it was creditable prescription drug coverage. Keep the employer or plan notice that confirms creditable coverage. Going 63 days or more without Part D or other creditable drug coverage after you are eligible can result in a Part D late-enrollment penalty unless an exception applies.
Forms you may encounter
People enrolling in Part B after delaying it because of employer coverage commonly use CMS-40B (Application for Enrollment in Medicare Part B) and CMS-L564 (Request for Employment Information) to document employer coverage. Social Security also offers online enrollment options in many situations.
What about retiree insurance?
Retiree coverage is not the same as insurance based on current employment. Some retiree plans require you to have Parts A and B and then pay secondary to Medicare. Ask the plan administrator exactly how the retiree coverage coordinates with Medicare before delaying enrollment.
Medicare vs. employer insurance: what should you compare?
| Question | Why it matters |
|---|---|
| Monthly and annual costs | Compare premiums, deductibles, copays, coinsurance and worst-case out-of-pocket exposure — not just the monthly premium. |
| Doctors and hospitals | Provider access and network rules can differ between employer coverage, Medicare Advantage and Original Medicare. |
| Prescriptions | Formularies, pharmacies, drug tiers and total drug costs can vary widely. |
| Spouse or dependents | Leaving employer coverage may affect other people who are covered under the plan. |
| HSA contributions | Medicare enrollment changes HSA contribution eligibility and may involve retroactive Part A. |
| Travel | Frequent travel or living in more than one area can affect which coverage structure fits better. |
After Parts A and B: two common coverage paths
After enrolling in Parts A and B, many people choose between Original Medicare, often paired with Part D and possibly Medigap, or a Medicare Advantage plan. Plan availability, provider networks, formularies and costs vary by county, which can be especially important in rural Texas.
Questions to ask HR before your last day
- What exact date does my active employee health coverage end?
- Is my coverage based on current employment?
- How does the plan coordinate with Medicare after age 65?
- Is the prescription coverage creditable for Medicare Part D?
- Can I get written verification of my employer coverage?
- Does the employer offer retiree coverage, and how does it coordinate with Medicare?
- If my spouse or dependents are covered, what happens to their coverage when I retire?
Common retirement-to-Medicare mistakes
Waiting until COBRA ends to enroll in Part B
COBRA generally does not extend the Part B Special Enrollment Period tied to current employment.
Assuming every employer plan lets you delay Medicare
Employer size, the type of coverage and who pays first all matter. Verify before delaying Part B.
Continuing HSA contributions too long
Retroactive Part A coverage can create an HSA contribution issue if timing is not coordinated.
Choosing coverage based only on premium
Doctors, prescriptions, networks and total annual costs may matter more than the advertised monthly premium.
Official references: Medicare — Working past 65, Medicare — COBRA coverage, and CMS — Medicare Secondary Payer.
Still have questions?
Medicare is personal. If you want help understanding how these rules fit your situation, Mike & Tracy can walk through it with you. There is no additional cost for our assistance.