You may have heard of a Medigap policy. But what is it, exactly?

Also known as Medicare supplement insurance, a Medigap policy is a type of private insurance policy. It’s designed to help fill the "gaps" in coverage left by original Medicare (Part A and Part B). Medigap policies are sold by private carriers. They’re meant to work alongside Medicare to provide additional benefits and help cover some of the costs Medicare does not pay for.

"A Medigap policy can give Medicare beneficiaries greater peace of mind by covering out-of-pocket costs like deductibles and coinsurance," said Ryan Ramsey, NCOA Associate Director of Health Coverage and Benefits. "It helps create financial predictability, especially for those with frequent medical needs or on a fixed income."

When can I buy a Medigap policy?

The best time to buy a Medigap policy is when you’re 65 or older and you first sign up for Medicare Part A and Part B. Typically, you need this coverage to buy a Medigap policy. This period is your Medigap Open Enrollment Period. You have six months after your Part B coverage starts to buy any Medigap policy sold in your state (even if you have pre-existing health problems).

In most cases, you cannot change your Medigap coverage outside your Medigap Open Enrollment Period. In every state except Connecticut, Maine, Massachusetts, and New York, if you apply for a Medigap policy after your first six months of Medicare eligibility, the insurance company can deny coverage (or charge you more due to a pre-existing condition). "A Medigap insurer can generally turn you down for whatever reason they see fit," Ramsey told Fortune Well.

Medicare.gov offers an online tool to help you find out if you have a legal right to switch or drop Medigap policies.

If you’re under age 65, you might not be able to buy a Medigap policy at all, or it may be more expensive. This is true even if you have Medicare and buy Medigap in the first six months after your Medicare coverage starts.

How can I choose a Medigap plan that’s right for me?

With so many options, choosing the right Medigap plan can feel overwhelming. Start by gathering some basic information. You can narrow down your choices simply by asking the right questions. Below are some questions to use when you’re speaking to insurance representatives about Medigap:

1. Am I enrolling while I am in my Medigap Open Enrollment Period? If not, do I have a guaranteed issue right? Guaranteed issue rights (also called "Medigap protections") are special situations in which you buy a Medigap policy outside of your Medigap Open Enrollment Period. See this online tool on Medicare.gov to find out if you can legally switch or drop Medigap policies.
2. What is the Medigap policy’s monthly premium? According to KFF, the average monthly Medigap premium in 2023 was $217¹, though this cost can vary quite a bit depending on the type of plan. Keep in mind you'll also be responsible for the Medicare Part B monthly premium ($202.90 in 2026).
3. Is my premium based on my health status, sex, smoking status, marital status, or anything else? Knowing this helps you understand why you're being charged a certain premium and whether you're getting fair pricing. It also allows you to shop smarter for Medigap policies and explore potential discounts that save you money every month.
4. How is the policy priced? Medigap policies uses three different pricing structures to determine premiums:
   
   • Community-rated (no-age-rated), meaning everyone in your area pays the same premium regardless of their age
   
   • Issue-age-rated (entry-age-rated), meaning the premium is based on how old you are when you buy the policy
   
   • Attained-age-rated, meaning the premium increases over time based on your age

   These structures affect how your Medigap premium costs may change over time. For instance, attained-age-rated plans may start out cheaper, yet usually get more expensive as you get older. While a low initial monthly cost may be appealing, steadily rising premiums can stretch your budget.

5. Will the company refuse to sell me a Medigap policy based on my health status? If you're applying outside of your Open Enrollment Period, insurance companies in most states can apply health-based surcharges or even deny you coverage outright. Note: Some states provide stronger consumer protections than what federal law requires. This makes it easier for residents to get Medigap coverage outside the standard Open Enrollment Period without facing denial of coverage for health reasons.
6. Does the policy impose a pre-existing condition waiting period? If you did not have at least six months of prior creditable coverage before enrolling or you don't have a guaranteed issue right, Medigap insurers can delay covering pre-existing conditions for up to six months. But original Medicare will still cover you during that time.
7. How long is the waiting period before my coverage begins? Most policies have no waiting period before coverage begins. But as mentioned above, if you lacked prior creditable coverage, any pre-exisiting conditions may not be covered for up to six months.
8. Do I have prior creditable coverage to reduce my waiting period? Prior creditable coverage includes health insurance you had for at least six months before you Medigap policy starts—such as Medicare Advantage, Medicaid, TRICARE, or another Medigap policy. If you had six months or more of creditable coverage, there is no waiting period for pre-existing conditions at all. If you had fewer than six months of coverage, the waiting period for pre-existing conditions is shortened by one month for every month you had creditable coverage before you bought the plan.

If you are under 65, make sure the company you are considering sells to people under 65. Also, keep track of who you spoke with, when you spoke with them, and the outcome of the call.

Ready to browse Medigap plans? You can explore different Medigap policy options using Medicare.gov's Medigap Policy Finder.

Source

1.  KFF. Key Facts About Medigap Enrollment and Premiums for Medicare Beneficiaries. October 18, 2024. Found on the internet at https://www.kff.org/medicare/key-facts-about-medigap-enrollment-and-premiums-for-medicare-beneficiaries/