Medicare Supplement Plans
Medicare Supplement — where it fits.
How "Medigap" plans pair with Original Medicare, the lettered plans, and when you can buy without underwriting.
What Medigap is
Medigap plans are sold by private insurers and pay your share of cost after Original Medicare pays its share. They are standardized lettered plans (Plan G, Plan N, Plan F for some grandfathered enrollees). Within each letter, benefits are identical across carriers — only the premium and customer service differ.
Key timing rule
You typically have a one-time Medigap Open Enrollment Period that begins the month you are 65 and enrolled in Part B. During that window, carriers cannot use medical underwriting to deny or surcharge you. Outside that window, rules vary by state.
What Medigap does not include
Medigap does not include Part D prescription drug coverage. If you go the Medigap route, you typically pair it with a standalone Part D plan.