Medigap Basics: Medicare Supplement Insurance Explained

Medicare Supplement Insurance – often called Medigap – is extra insurance you can buy from a private company to help pay your share of costs in Original Medicare. These policies are designed to cover out-of-pocket expenses like deductibles, copayments, and coinsurance.

You can only buy a Medigap policy if you are enrolled in Medicare Part A (Hospital Insurance) and Medicare Part B (Medical Insurance).

When Can You Enroll?

Your one-time Medigap Open Enrollment Period starts the month you turn 65 and are enrolled in Part B. For six months, you can buy any Medigap plan sold in your state, and insurance companies can’t deny you or charge more due to pre-existing conditions. After this window closes, you may have fewer choices or pay higher premiums.

Note: The Medigap Open Enrollment Period is not the same as Medicare’s Annual Open Enrollment (Oct 15–Dec 7). It happens only once.

Standardized Plans

All Medigap plans are standardized by federal law. This means that a Plan G sold by one insurer offers the same benefits as a Plan G sold by another – the only difference is price. Most states offer up to 10 lettered plans: A, B, C, D, F, G, K, L, M, and N.

A special type called Medicare SELECT may also be available. These plans require you to use certain hospitals and providers. If you change your mind within 12 months, you can switch to a standard Medigap policy.

Important: Massachusetts, Minnesota, and Wisconsin standardize Medigap differently, with their own versions of coverage.

What Medigap Covers

Medigap plans help pay for:

• Medicare Part A and B deductibles
• Coinsurance and copayments
• Blood (first 3 pints)
• Hospice care coinsurance

Some plans also cover care outside the U.S. during emergencies (foreign travel emergency coverage).

What Medigap Does Not Cover

Medigap plans generally do not cover:

• Long-term care (such as nursing home stays)
• Routine vision or dental services
• Hearing aids
• Eyeglasses
• Private-duty nursing

Medigap policies sold after 2005 do not include prescription drug coverage. If you want drug coverage, you’ll need to enroll in a separate Medicare Part D plan.

How Medigap Works With Medicare

A Medigap policy only covers one person. If you and your spouse both want coverage, you’ll need to buy separate policies.

When you receive care, Medicare pays its share of approved costs. Then, your Medigap policy pays its share according to the plan benefits. Many insurers handle claim coordination automatically so your provider gets paid directly.

Once you buy a Medigap policy and keep paying premiums, it is guaranteed renewable. The company can’t drop you because of health problems. They can only cancel if:

• You stop paying premiums
• You misrepresented information on your application
• The company goes bankrupt or leaves the Medigap market