What Is Aarp Medigap Insurance? 
AARP is a politically active lobbying organization and marketing entity , not an insurance carrier . They currently endorse Medigap -LRB- Medicare supplement -RRB- plan underwritten and administered by United Healthcare . Medigap plans are designed to cover the `` gaps '' in Medicare created by deductibles and coinsurance . All Medigap plans are standardized and vary -LRB- within the same letter -RRB- only by price . 