About 87% of beneficiaries enrolled in fee-for-service Medicare programs have Medicare supplemental insurance policies (most are a form of Medigap insurance), which pay for some or all of Medicare deductibles and co-payments, typically in Parts A and B. People must be enrolled in Parts A and B to be eligible to purchase Medigap insurance. People enrolled in the Medicare Advantage plan (Part C) cannot purchase a Medigap policy unless they leave the Medicare Advantage plan and return to Original Medicare. Most Medigap insurance is purchased individually from private insurers, although employers may reimburse Medigap premiums (or provide similar coverage in a retiree plan) to retirees.
There are 10 different types of Medigap insurance available, labeled A-D, F, G, and K-N. Benefits are the same for all plans with the same letter, regardless of insurance carrier. No plan may duplicate Medicare benefits. The basic plan (Plan A) covers
The other plans, which have higher premiums than Plan A, may provide additional coverage in a skilled nursing facility and may cover Part A and Part B deductibles, preventive medical services, and short-term home-based help with activities of daily living (ADLs) during recovery from an illness, injury, or surgery. Some of these plans, if purchased before Medicare Part D took effect, covered a percentage of the cost of outpatient prescribed drugs.
The Medigap initial enrollment period begins the month people turn 65 and lasts 7 months. During this period, people who have preexisting conditions cannot be denied coverage or charged more; however, after this period, insurers may deny coverage or charge more due to a preexisting condition.