Americans are working longer. Many people reach 65 — Medicare's standard eligibility age — while still employed and covered by a workplace health plan. This creates a common question: do I have to enroll in Medicare right now, or can I wait?
The answer depends on several factors, and getting it wrong can have permanent financial consequences. Here's what you need to know.
The Critical Variable: Employer Size
The most important factor is how many employees your employer has — specifically, whether they have fewer or more than 20 employees.
- Employer has 20 or more employees: Your employer's group health plan is "primary" — it pays first. Medicare would be secondary. In this case, you can generally delay enrolling in Part B without penalty, as long as your employer coverage remains active. When your coverage ends, you have an 8-month Special Enrollment Period to enroll in Part B.
- Employer has fewer than 20 employees: Medicare is primary — it pays first. If you don't enroll in Part B at 65, Medicare will refuse to pay for services it would have covered, leaving your small-group plan to pay what it otherwise wouldn't. This can result in significant out-of-pocket exposure, and you'll still face a late enrollment penalty later.
Part A: Usually Enroll at 65 Regardless
If you've worked at least 10 years and paid Medicare taxes, Part A (hospital insurance) is premium-free. In most cases, it makes sense to enroll in Part A at 65 even if you're still working — it can provide secondary coverage alongside your employer plan. The main exception: if you have a Health Savings Account (HSA), see below.
HSA Users: Important Restriction
If you contribute to a Health Savings Account (HSA) through your employer's high-deductible health plan, enrolling in any part of Medicare — including Part A — makes you ineligible to continue contributing to the HSA. You must stop HSA contributions six months before Medicare begins (because Medicare Part A can be backdated up to six months).
If maximizing HSA contributions is a priority, you may want to carefully time your Medicare enrollment. This is an area where personalized advice is particularly valuable.
Spouse's Employer Coverage
If you're covered as a dependent on your spouse's employer plan, the same employer size rule applies — based on your spouse's employer's headcount. Losing that coverage (because your spouse retires or loses the job) triggers your own 8-month SEP for Part B.
COBRA Is Not the Same as Active Coverage
If you elect COBRA when you leave employment, COBRA drug and medical coverage does not count as employer-sponsored coverage for purposes of delaying Medicare Part B or Part D. Once active employer coverage ends, the Medicare clock starts — even if you're on COBRA. Enrolling in Medicare and dropping COBRA is usually the right move.
Get Personalized Guidance
The intersection of employer coverage and Medicare has traps for the unwary. Whether you're approaching 65 or helping a parent navigate this decision, call Insurance Innovators LLC at (530) 395-5309. We'll walk through your specific situation and help you avoid costly mistakes.