Medicare Supplement Plans in Michigan for 2027: 10 Letters and the 6-Month Window

What does a Medicare Supplement plan pay for in Michigan?

A Medicare Supplement policy, also called Medigap, pays costs that Original Medicare leaves to you. Michigan DIFS describes these policies as coverage that helps pay health care costs Medicare does not pay, including deductibles and coinsurance. You keep Part A and Part B, and the Medigap policy pays after Medicare pays.

Medigap does not cover prescription drugs, routine dental, vision, or hearing. You still pay the Part B premium, which was $202.90 a month in 2026 for most people. You also still need a separate drug plan, which is covered on our Part D hub.

All Medigap policies are standardized. Policies with the same letter offer the same basic benefits no matter where you live or which company sells them. That is why the letter you choose matters more than the logo, a point we work through in our Medicare hub.

Which of the 10 standardized plans can Michigan residents buy?

Medicare.gov lists 10 Medigap plan types in most states, named A through D, F, G, and K through N. Michigan uses those same federal letters. Plans C and F are limited: your eligibility depends on when you first became eligible for Medicare, and people who became eligible on or after January 1, 2020 generally cannot buy them.

The table below compares the letters most Michigan applicants shortlist, using 2026 figures published by Medicare. CMS releases the following year’s Part A and Part B amounts in a fall announcement, so the 2027 versions of these numbers arrive before January 1.

Most Michigan shortlists come down to Plan G, Plan N, or high-deductible Plan G. We break the tradeoffs down letter by letter in our guide to Plan G versus Plan N and the 10 letters, including who the office-visit copays actually affect.

When does your Michigan Medigap open enrollment window start?

Federal law gives you a six-month Medigap Open Enrollment Period. It starts the first month you have Medicare Part B and you are 65 or older. During that window you can enroll in any Medigap policy the company sells, and it cannot use medical underwriting or charge you more because of pre-existing health problems.

This window is one-time. It does not repeat each year the way the Annual Enrollment Period does, and it is not tied to October 15 to December 7. If you delayed Part B because you were still working, your six months begin when your Part B coverage starts.

What happens if you apply after the six-month window closes?

Michigan DIFS is direct about this. If you apply for a Medicare Supplement policy after your six-month open enrollment period, you are subject to the insurer’s medical underwriting criteria and may be denied or rated based on your health conditions.

There are exceptions. DIFS notes you may be able to buy a policy with guaranteed-issue rights when you lose other health coverage, and Medicare.gov tells beneficiaries to check with their state insurance department for additional rights under state law. Guaranteed-issue and underwriting rules vary by state, so a rule you read about elsewhere may not apply in Michigan. The most common exception is the 63-day right described in our post on switching from Medicare Advantage to Medigap.

Michigan also has a group-coverage path. State law requires insurers offering group medical coverage to make available a continuation or conversion right into a core-benefit plan or Plan C or Plan F for people who lose group coverage after becoming Medicare eligible. For anyone newly eligible after December 31, 2019, references to Plan C and Plan F are read as Plan D and Plan G.

Under-65 Michigan beneficiaries have fewer options. DIFS states that choices are generally limited to Plan A or Plan C, and that only a limited number of health insurers must offer them to people under 65.

How are Michigan Medicare supplement rates set and reviewed?

Michigan law bars an insurer from using or changing Medicare Supplement premium rates unless the rates, rating schedule, and supporting documentation have been filed with and approved by the state regulator. That is the sourcing edge available to Michigan shoppers: approved rate activity is a public record, not a marketing claim.

Those filings sit in SERFF Filing Access for Michigan, where rate, form, and rule filings can be inspected and downloaded at no cost. DIFS also publishes a list of companies authorized to write and actively writing Medicare Supplement insurance in the state.

Two questions are worth asking before you sign anything. First, how is this policy rated, meaning does the premium change as you age. Second, what has this company’s Michigan rate-change history looked like over the last several years. Benefits are fixed by letter, so those two answers drive your long-run cost.

Medigap or Medicare Advantage in Michigan for 2027?

Michigan leans hard toward Medicare Advantage. KFF puts the state at the top of the national range, with about 63 percent of eligible beneficiaries enrolled in Medicare Advantage. That means most Michigan retirees are choosing networks and plan-level out-of-pocket maximums over a monthly Medigap premium.

The honest tradeoff is provider access and predictability versus premium. Medigap has no network and pays alongside Original Medicare, but you pay a premium plus a separate Part D plan. Medicare Advantage bundles more, with networks and prior authorization rules attached. We lay out both sides in our Medicare Advantage versus Medigap comparison for 2027.

Timing is the part people underestimate. Leaving Medigap is easy; coming back later can require underwriting. The same six-month and 63-day mechanics show up in every state we serve, including in our Texas Medigap guide, but the guaranteed-issue details are state-specific.