A Medicare Supplement (Medigap) insurance, sold by private companies, can help pay some of the health care costs that Original Medicare doesn't cover, like co-payments, coinsurance, and deductibles.
If you have Original Medicare and you buy a Medigap policy, Medicare will pay its share of the Medicare-approved amount for covered health care costs usually about 80% and your chosen Medigap policy will cover all or some of the remaining 20%.
What you need to know about Medicare Supplement policies.
You must have Medicare Part A and Part B.
If you have a Medicare Advantage Plan, you can switch to a Medicare Supplement insurance policy, but make sure you can leave the Medicare Advantage Plan before your Medicare Supplement insurance policy begins.
You pay the private insurance company a monthly premium for your Medicare Supplement insurance policy in addition to the monthly Part B premium that you pay to Medicare.
A Medigap policy only covers one person. If you and your spouse both want Medigap coverage, you'll each have to buy separate policies.
You can buy a Medicare Supplement insurance policy from any insurance company that's licensed in your state to sell one.
Any standardized Medicare Supplement insurance policy is guaranteed renewable even if you have health problems. This means the insurance company can't cancel your Medicare Supplement insurance policy as long as you pay the premium.
Medicare Supplement insurance policies sold after January 1, 2006, aren't allowed to include prescription drug coverage. If you want prescription drug coverage, you can join a Medicare Prescription Drug Plan (Part D).
It's illegal for anyone to sell you a Medigap policy if you have a Medicare Advantage Plan unless you're switching back to Original Medicare.