He Turned 65, Kept the Company Plan, and Medicare Was Already First in Line

This week we are doing something different.

Almost nobody arrives at Medicare the same way. The rules are written as though everyone turns 65 on a Tuesday, walks away from a job, and signs up. Almost no one we meet actually does that. They come in sideways, from a business they still run, from a job they were asked to leave, from military service, from a marriage where two people are five years apart in age.

So for the next seven days we are walking through seven real doors into the same program. Different people, different rules, and in each case one small detail that decided the whole outcome. Today, the business owner.

If I own a business and turn 65, does my group health plan still pay first?

It depends entirely on how many people work for you, and the line is drawn at twenty.

If your company has 20 or more employees, your group plan pays first and Medicare pays second. If your company has fewer than 20, it is the reverse. Medicare pays first and your group plan pays second. That is true whether or not you have enrolled in Medicare.

That last sentence is the one that costs people money, and it is the reason this article exists.

The twenty employee line

Here is how Medicare states it, in its own words, on the page it publishes for exactly this question:

"If you have non-tribal group health plan coverage through an employer who has 20 or more employees, the non-tribal group health plan pays first, and Medicare pays second. If you have non-tribal group health plan coverage through an employer who has fewer than 20 employees, Medicare pays first, and the non-tribal group health plan pays second."

You can read that in full on Medicare's Who Pays First guidance.

The government side of this has a name. The Centers for Medicare and Medicaid Services calls it the Small Employer Exception, and its own description is blunt about what happens at a company under the threshold. For a business with fewer than 20 full or part time employees, the rules that would normally make Medicare the secondary payer "do not apply."

Both full time and part time employees count toward the twenty. A great many of the professional practices, small manufacturers, agencies and family businesses our advisors sit down with are under that number and have no idea it matters.

What "Medicare pays first" means if you never enrolled

This is the part that surprises people, so let me be careful and precise about it, because the honest version is narrower than the scary version you may have heard.

Medicare does not send you a bill for a program you did not join. What happens instead is quieter. When Medicare is designated the primary payer, your group plan is only ever the secondary payer on those claims. And insurance companies write their contracts accordingly.

Medicare's own guidance for people working past 65 puts it this way:

"Some private insurance companies have rules that lower what they pay (or don't pay at all) for services you get if you're eligible for other coverage, like Medicare."

Read that again with a business owner's eyes. Not "if you have other coverage." If you are eligible for it.

So the exposure is not theoretical, and it is not automatic either. It lives in the language of your specific plan document. Medicare's advice on that page is the same advice we would give: contact your health plan and ask directly. The question to ask is short. If I am 65 and eligible for Medicare, does this plan pay as primary or as secondary on my claims?

A business owner who assumed he was fully covered, at a company of eleven people, can be carrying a much thinner policy than he thinks. Usually he finds out in a year when nothing happens, which is to say he never finds out at all. Occasionally he finds out in a year when something does.

How much is the Part B late enrollment penalty?

The second cost is easier to calculate, and it is permanent.

If you could have signed up for Part B and did not, and no Special Enrollment Period applies to you, Medicare adds 10 percent to your premium for each full 12 month period you waited. Not once. On the monthly premium.

Medicare publishes the arithmetic itself, using this year's numbers. The standard Part B premium in 2026 is $202.90 a month. Someone who waited two full years and did not qualify for a Special Enrollment Period pays a 20 percent penalty on top, which works out like this:

"$202.90 (2026 Part B standard premium) + $40.58 (20% [of $202.90] late enrollment penalty) = $243.48. $243.50 will be your Part B monthly premium for 2026."

That example lives on Medicare's page about avoiding penalties. For reference, the 2026 Part B deductible is $283, and both figures come from the Centers for Medicare and Medicaid Services fact sheet released for this year.

Forty dollars a month does not sound like much on the day you read it. Run it out over a twenty five year retirement and you are looking at more than twelve thousand dollars, for a decision made once, by accident, in a year nobody was paying attention.

Sometimes the right answer is to keep the group plan

I want to be fair here, because the internet is full of people telling business owners that Medicare is always cheaper and that is simply not true.

From the conversations our advisors have, some of the most useful meetings end with a recommendation to change nothing at all. A business owner at a company of sixty people, with a rich plan and a spouse and two adult children on it, is often better off exactly where he is. His plan pays first. It is doing its job.

The point is not that group coverage is bad. The point is that the twenty employee line quietly decides which of two completely different sets of rules you are living under, and almost nobody checks which side they are on before it matters.

There is also a real cost question underneath it. For an owner paying the full loaded premium on a small group plan, Medicare plus a supplement can genuinely come out ahead. For an owner at a larger company with a subsidized plan, it usually does not. That comparison is arithmetic, and it is worth doing once, properly, on paper.

The eight month window that starts sooner than you think

One more thing, and it sets up tomorrow.

When you do stop working, you get a Special Enrollment Period to pick up Part B without a penalty. It runs eight months. Here is the detail almost everyone gets wrong, straight from Medicare's enrollment guidance:

"Your 8-month Special Enrollment Period to sign up for Part B starts when you stop working, even if you choose COBRA or other coverage that's not Medicare."

When you stop working. Not when your coverage ends.

That single distinction is going to be the entire story tomorrow, and it is the most expensive misunderstanding in this whole subject.

What to do this week

If you own a business and you are anywhere near 65, three questions are worth answering before the end of the month.

1. How many employees do you actually have?

Count full time and part time. If the number is close to twenty, find out exactly where you land, because the answer changes which set of rules applies to you.

2. What does your plan document say about Medicare eligible employees?

Call the plan and ask whether it pays primary or secondary for an employee who is 65 and eligible for Medicare. Get the answer from the carrier, not from the person who sold you the plan.

3. Have you ever actually run the comparison?

Your loaded group premium against Medicare plus a supplement, for you specifically, at your age, with your prescriptions. Most owners have never seen the two numbers side by side.

If you would like a second set of eyes on it, our advisors at American Retirement Advisors do this comparison with business owners regularly, and there is no cost to you for the conversation.

Tomorrow: a woman who was let go at 68, handed two years of COBRA, and came to see us six months into it. Whether she made it in time is a closer call than it sounds.

This is part one of Seven Ways In, a seven part series on how seven very different people arrived at the same program, and the one detail that decided each case.

Disclaimer: This article is for educational purposes only. It is not sponsored, endorsed, or otherwise representative of Medicare or the federal Medicare program. American Retirement Advisors is not a government agency. For official Medicare information, visit medicare.gov or call 1-800-MEDICARE (1-800-633-4227).