What does a small business owner need to know when an employee is turning 65 and has group health insurance? The number that decides almost everything is whether the business has fewer than 20 employees or 20 or more, because that determines which coverage pays first. From there, the employee needs to know whether the group plan counts as creditable coverage before their Medicare enrollment window closes.
The Number That Changes Everything: How Many People Are on Payroll?
Before any other question gets answered, one figure settles the foundation. If the business has fewer than 20 employees, Medicare is generally the primary payer and the group plan is secondary. If the business has 20 or more employees, the group plan generally pays first and Medicare is secondary. Most owners have never been told this rule exists. Most employees turning 65 have no idea it applies to them. And yet it changes the financial calculation for the employee completely.
If Medicare pays first and the group plan pays second on a small employer plan, an employee who skips Medicare Part B may be left with significant cost exposure. The group carrier may deny or reduce claims that Medicare would have covered, because it expects Medicare to have paid its share first. That is not a technicality. That is real money at stake.
This rule is called the Medicare Secondary Payer rule. It is federal law, and it applies based on how many people are enrolled in the group health plan, not just the total headcount. Ask your plan administrator or benefits attorney to confirm how the count is calculated for your specific plan before advising employees.
What Does the Owner Actually Have to Do?
The owner is not required to become a Medicare expert, and is not supposed to advise employees on their personal coverage decisions. Those are individual choices that depend on each person’s health, finances, and the specifics of their plan. What the owner can do is make sure employees know the question exists before their enrollment window closes.
Practically speaking, that means notifying employees approaching 65 that Medicare enrollment periods are time-sensitive and that missing them can create permanent penalties. Point them toward Medicare.gov or toward a licensed Medicare broker who can review their specific situation. That is not legal advice. That is basic information that protects both the employee and the business.
There are also employer reporting obligations under Medicare Secondary Payer rules. Those sit with the plan and the employer, not the employee. If you are not sure whether your plan is reporting correctly, your benefits administrator or a compliance attorney is the right resource.
What Does “Creditable Coverage” Mean and Why Does It Matter?
Creditable coverage is the single most important concept for an employee on a group plan who is turning 65. A group health plan is considered creditable for Part B purposes when it is at least as good as Medicare’s standard coverage. A Part D drug plan is creditable when it meets CMS’s actuarial equivalence standard. If the plan qualifies, the employee can generally delay Part B and Part D enrollment without a penalty.
If the plan does not qualify, delaying Medicare creates a late enrollment penalty that adds to the monthly premium for as long as the person has Medicare. That is not a one-time fee. It compounds over time and never goes away.
The plan administrator can confirm in writing whether the plan is creditable. Ask for that confirmation in writing and keep it. If an employee delays based on a verbal assurance that later turns out to be wrong, the penalty still applies. The written confirmation matters.
Most employer-sponsored group health plans do qualify as creditable coverage for Part B. Part D creditable status is a separate determination and is confirmed annually. Do not assume one applies just because the other does.
The HSA Problem Nobody Mentions Until It Is Too Late
Contributing to a Health Savings Account after enrolling in Medicare Part A is not allowed. That is the rule. The part that catches people is that Part A enrollment can be retroactive by up to six months when you sign up after age 65.
Here is what that means in practice. Someone who waits until age 66 to sign up for Medicare may find that their Part A coverage reaches back to age 65 and a half. Any HSA contributions made during that retroactive period become a problem. The IRS treats them as excess contributions, and there are tax consequences.
The pattern I see most often is someone who stayed on the group plan, kept funding the HSA right up until their Medicare application, and then discovered the retroactive coverage window after the fact. Nobody told them. The fix is to stop HSA contributions at least six months before you intend to apply for Medicare, to leave room for the lookback period. If the employer contributes to the HSA as well, those contributions count toward the same limit and create the same issue.
This is one of the more technical intersections in this whole topic, and it is one of the things I always ask about before advising anyone near this decision.
The Owner’s Own Question: Is the Group Plan Still the Right Choice?
Small group coverage is expensive. That is not an opinion, it is the experience of nearly every small business owner who has renewed a group plan recently. What rarely gets said plainly is this: a lower-cost plan with a higher deductible, combined with a well-chosen supplemental policy, often produces a better total cost outcome than a richer group plan.
Most brokers do not frame it that way because selling a richer group plan generates a higher commission. I am not interested in that math. What I care about is whether the total cost picture makes sense for the business and the employees.
For employees turning 65 who have Medicare available, the calculus shifts further. If Medicare becomes primary, the group plan’s role changes. Some employers in that situation find that a leaner group offering paired with Medicare coverage for eligible employees lowers costs on both sides. That is worth modeling before the next renewal.
What Happens When an Employee Retires or Loses Coverage?
Loss of employer-sponsored group health coverage is a qualifying life event that opens a Special Enrollment Period for Medicare. That window is generally eight months from the date coverage ends or the employment ends, whichever comes first. It is not eight months from the date the employee knew coverage was ending. It starts when it starts.
If an employee misses that window, they fall into the General Enrollment Period, which runs January 1 through March 31, with coverage starting July 1. They may also face a late enrollment penalty if their gap in coverage was long enough. The options narrow permanently if the deadline is missed.
The right move is to start the conversation before the retirement date, not after. An employee who has been on a creditable group plan and retires at 67 has a clean path to Medicare enrollment. An employee who retires and waits six months to deal with it may not.
When You Need to See the Plan Document
This is one area where the right answer genuinely depends on the specific plan document. Two businesses can have group plans that look identical from the outside and have completely different answers to the creditable coverage question. I ask to see the plan document before advising anyone in this situation, and I would rather say that plainly than give a generic answer that turns out to be wrong.
If you are an owner with employees approaching 65, the most useful thing you can do right now is pull the plan document and ask your administrator two questions: Is this plan subject to Medicare Secondary Payer rules? And is it creditable for Part B and Part D purposes? Those two answers shape everything else.
If you want to work through how Medicare fits with your group plan situation, take the Medicare Clarity Score to get a baseline on where the gaps are. It takes about three minutes and gives you a clear starting point for the conversation.
You can also review the broader 2026 Medicare coverage and costs guide for context on Part B and Part D costs, or look at Medicare enrollment periods to understand exactly which windows apply and when they open and close.
We do not offer every plan available in your area. Any information we provide is limited to those plans we do offer in your area. Please contact Medicare.gov or 1-800-MEDICARE to get information on all of your options. Not affiliated with or endorsed by the federal government or the federal Medicare program.