Medigap Definition

What Is Medigap Insurance?

Medigap, also called Medicare Supplement Insurance, is health insurance coverage provided by private companies designed to pay for costs not covered by Original Medicare. Depending on which plan you get, these costs might include copayments, coinsurance, and deductibles, as well as services Original Medicare doesn't cover, such as travel outside of the U.S.

Key Takeaways

  • You can buy Medigap insurance from a private insurance company to pay for costs not covered by Original Medicare.
  • There are 12 standardized Medigap plans approved by the federal government.
  • Medigap plans don't cover the costs of prescription drugs—for that, you need to get a Medicare Prescription Drug Plan (Part D).
  • You can buy Medigap during an open enrollment period after you turn 65.
  • Your insurance company can't cancel the policy if premiums are paid, even if you experience health problems.

Medigap vs. Medicare Advantage: What's the Difference

Understanding Medigap Insurance

Original Medicare—defined as Parts A and B—will not cover all expenses associated with an illness. Medigap policies are designed to cover all or a portion of those extra charges, depending on the type of coverage, but generally don’t include long-term care, vision, dental care, hearing aids, eyeglasses, or private nursing.

Although private insurance companies offer Medigap coverage, the federal government requires companies to offer standardized policies. Your 12 choices are plans A, B, C, D, F, F-High Deductible, G, G-High Deductible, K, L, M, and N.

However, for those who become newly eligible for Medicare in 2020 and after, plans C, F, and F-High Deductible are no longer available. That’s because these plans cover the Medicare Part B deductible, the amount you have to pay before coverage kicks in, which is $233 in 2022 (up from $203 in 2021) and $226 in 2023.

Congress passed the Medicare Access and CHIP Reauthorization Act (MACRA) in 2015, which disallowed such coverage. The intention was to make people pay at least a little bit for health care to prevent them from running straight to the doctor for every scrape, scratch, or sniffle. Fortunately, those who are already enrolled in plans C, F, and F-High Deductible will be able to keep them going forward. In addition, people eligible for Medigap before Jan. 1, 2020, who did not enroll in a plan may still be able to buy them.

A Medigap policy covers coinsurance only after you've paid the deductible (unless the Medigap policy also pays the deductible).

Requirements for Medigap Coverage

Monthly premiums for a Medigap policy are paid to a private insurance company that is licensed to sell such policies in your state and are in addition to the monthly premium for Medicare Part B. A policy only covers one person. So, if you and your spouse want coverage, you each need a separate Medigap policy.

Furthermore, according to

"The best time to buy a Medigap policy is during your 6-month Medigap Open Enrollment Period...During that time you can buy any Medigap policy sold in your state, even if you have health problems. This period automatically starts the first month you have Medicare Part B (Medical Insurance) and you're 65 or older...After this enrollment period, you may not be able to buy a Medigap policy. If you're able to buy one, it may cost more due to past or present health problems."

Shopping for Medigap coverage is straightforward because you merely compare prices and the suitability of the insurance company. Once you have a Medigap policy, it is guaranteed renewable, even if you have health problems. In other words, the insurance company cannot cancel the policy so long as the premiums are paid.

Medigap coverage does not work with a Medicare Advantage Plan (Part C). Indeed, if you have a Medicare Advantage Plan, it is illegal for someone to sell you Medigap coverage. However, if you have Medicare Advantage and are unhappy with the plan, you can switch to Original Medicare within the first 12 months, at which point you can buy Medigap coverage.

CARES Act of 2020

On March 27, 2020, President Trump signed a $2 trillion coronavirus emergency stimulus package, called the CARES (Coronavirus Aid, Relief, and Economic Security) Act, into law. It expands Medicare's ability to cover treatment and services for those affected by COVID-19. The CARES Act also:

  • Increases flexibility for Medicare to cover telehealth services.
  • Authorizes Medicare certification for home health services by physician assistants, nurse practitioners, and certified nurse specialists.
  • Increases Medicare payments for COVID-19–related hospital stays and durable medical equipment.

The CARES Act also clarifies that non-expansion states can use the Medicaid program to cover COVID-19–related services for uninsured adults who would have qualified for Medicaid if the state had chosen to expand. Other populations with limited Medicaid coverage are also eligible for coverage under this state option.

Is There Anything Medigap Doesn't Cover?

Medigap policies tend to lack coverage for dental, vision, long-term care, and private-duty nursing.

Can I Have Medigap and Medicare Advantage (Part C)?

No, having both Medigap and Medicare Advantage (Part C) is not legal. If you want to switch from one plan to the other, that is possible within the first 12 months of coverage.

Who Can I Talk to About Medigap Questions?

If you have additional questions, there are a few options. You can check out this link for a live chat feature or call customer service at 1-800-MEDICARE (1-800-633-4227). 

Article Sources
Investopedia requires writers to use primary sources to support their work. These include white papers, government data, original reporting, and interviews with industry experts. We also reference original research from other reputable publishers where appropriate. You can learn more about the standards we follow in producing accurate, unbiased content in our editorial policy.
  1. U.S. Centers for Medicare & Medicaid Services. "What's Medicare Supplement Insurance (Medigap)?"

  2. U.S. Centers for Medicare & Medicaid Services. "When Can I Buy Medigap?"

  3. U.S. Centers for Medicare & Medicaid Services. "What's Medicare Supplement Insurance (Medigap)?"

  4. U.S. Centers for Medicare & Medicaid Services. "How to Compare Medigap Policies."

  5. U.S. Centers for Medicare & Medicaid Services. “2023 Medicare Parts A & B Premiums and Deductibles 2023 Medicare Part D Income-Related Monthly Adjustment Amounts."

  6. U.S. Centers for Medicare & Medicaid Services. "MACRA."

  7. U.S. Centers for Medicare & Medicaid Services. "Switching Medigap Policies." c

  8. U.S. Centers for Medicare & Medicaid Services. "Medigap & Medicare Advantage Plans."

  9. U.S. Congress. "H.R.748 - CARES Act."

  10. U.S. Centers for Medicare & Medicaid Services. "Medigap & Medicare Advantage Plans."