The New Medicare Card mailing is complete! Everyone currently on Medicare should have their new card with the randomly-generated Medicare number replacing Social Security Numbers on Medicare cards and in Medicare systems. This number is also known as the Medicare Beneficiary Identifier (MBI).
The biggest reason CMS took the SSN off of Medicare cards is to fight medical identity theft for people with Medicare.
By replacing the SSN-based HICN on all Medicare cards, the federal government is better protecting:
Private health care and financial information.
Federal health care benefit and service payments.
The MBI is confidential like the SSN and should be protected as Personally Identifiable Information, protect this card just as you would protect a credit card.