The Medicare Access and CHIP Reauthorization Act (MACRA) of 2015, requires CMS to remove Social Security Numbers (SSNs) from all Medicare cards by April 2019. A new Medicare Beneficiary Identifier (MBI) will replace the SSN-based Health Insurance Claim Number (HICN) on the new Medicare cards for Medicare transactions like billing, eligibility status, and claim status. The biggest reason CMS is taking the SSN off of Medicare cards is to fight medical identity theft for people with Medicare. Beginning in April 2018, CMS will start sending the new Medicare cards with the MBI to all people with Medicare. They plan to have a transition period where you can use either the HICN or the MBI to exchange data with them. The transition period will begin no earlier than April 1, 2018 and run through December 31, 2019. The new MBI will be 11-characters in length and made up only of numbers and uppercase letters (no special characters).