A supplemental plan in Medicare, often referred to as Medigap, is a type of private insurance designed to help cover costs not included in Original Medicare Parts A and B. 

These costs can include copayments, coinsurance, and deductibles.

 Medigap plans are specifically designed to supplement your Medicare coverage by paying for out-of-pocket expenses, thereby reducing the extra costs you might face with just Medicare alone. 

However, it’s important to note that Medigap plans do not cover prescription drugs, which are covered under 

Medicare Part D. 

Several well-known health insurance companies offer Medicare supplement Medigap plans.  Some of the major providers include:

Aetna, United Healthcare (partnered with AARP), Cigna, Blue Cross Blue Shield, Mutual of Omaha, and Humana. 

The availability of these plans and their premiums can vary depending on your location.