Working Past 65: Should You Stay on Your Employer Health Plan?
More Americans are working well beyond 65 than ever before. But staying on your company insurance requires careful navigation of the federal 20-employee rule, creditable drug coverage criteria, and Health Savings Account (HSA) contribution freezes.
The Company Size Benchmark: 20 Employees
Federal law dictates who pays your medical bills first based strictly on how many employees your company (or your spouse's company) has:
20 or More Employees (Large Group)
If your company employs 20 or more people, your group health plan is considered the Primary Payer. Medicare is secondary.
Under 20 Employees (Small Group)
If your employer has fewer than 20 workers, Medicare automatically becomes your Primary Payer on your 65th birthday, and your group plan is secondary.
What Does "Creditable Drug Coverage" Mean?
By law, every employer providing prescription drug benefits must send active employees a "Notice of Creditable Coverage" every September/October before open enrollment.
Definition of "Creditable":
It means your employer’s prescription plan is expected to pay, on average, at least as much as the standard Medicare Part D prescription drug benefit.
What if your employer's plan is NOT creditable?
Some high-deductible or small group plans fail the creditable test! If your employer plan is non-creditable, you must enroll in a standalone Medicare Part D plan at 65, or you will face a 1% per month permanent late enrollment penalty for every month you go without it.
Always Keep the Creditable Coverage Letter!
Do not discard this letter! When you eventually retire and sign up for Medicare Part D, Medicare will ask you to produce proof that you had continuous creditable prescription coverage since turning 65.
The Health Savings Account (HSA) Contribution Freeze
If you or your employer contribute to a Health Savings Account (HSA), signing up for any part of Medicare (even free Part A) immediately makes you ineligible to make further HSA contributions under IRS tax code.
The 6-Month Retroactive Part A Rule
When you apply for Medicare Part A after age 65, the federal government makes your Part A start date retroactive by 6 months (or back to your 65th birthday month).
Stop HSA Contributions 6 Months in Advance
To avoid severe IRS excise tax penalties (6% per year on excess contributions), you and your employer must stop all HSA contributions at least 6 months before you apply for Medicare Part A!
* Note: You can still spend existing money already in your HSA on qualified medical expenses, Medicare premiums, and copays tax-free—you just cannot make new deposits.
Ready to Retire? The 8-Month Special Enrollment Period (SEP)
When you decide to leave work (or your spouse leaves work), you trigger an 8-month Special Enrollment Period to enroll in Medicare Part B without penalty:
Fill out Form CMS-40B
Your application to enroll in Medicare Part B.
Have HR Sign CMS-L564
Proof of Employment Group Health Coverage signed by your company HR.
Submit to SSA & Pick Plan
One Care Benefits Group coordinates your Medigap or Advantage start date with zero coverage gap.
Want a free comparison of your employer plan vs. Medicare?
Bring your group benefit summary and our advisors will run a side-by-side cost and coverage check.