Medicare Beneficiary Identifier

Acronym: MBI

The MBI is a unique Medicare Number assigned to each beneficiary. This number replaces the previous Social Security-based Health Insurance Claim Number (HICN) on new Medicare cards for Medicare transactions like billing, eligibility status, and claim status. In the past and through 12/31/2019, CMS used an SSN-based HICN to identify people with Medicare and administer the program. Congress ordered CMS to remove the SSN from Medicare cards is to fight medical identity theft for people with Medicare. A new Medicare Beneficiary Identifier (MBI) replaced the SSN-based Health Insurance Claim Number (HICN) on the new Medicare cards for Medicare transactions like billing, eligibility status, and claim status.