 [ Symptoms ] can a marketplace plan be used as a supplemental policy with medicare as the primary [ Disease ] you are most likely better off purchasing a medigap policy than purchasing a full medical policy through the marketplace medigap policies are designed to wrap around medicare coverage and fill in the gaps in coverage to get help finding a medigap policy you can contact your local state health insurance assistance program  <link>  there is nothing to prevent you from purchasing a policy on the marketplace but you would not qualify for a premium subsidy because you already have medicare and it may not be the best policy for you given you have other coverage