TN 9 (01-23)

HI 00901.040 New Medicare Numbers and Number Change Requests

A. Background on the new Medicare Number

The Medicare Access and Children’s Health Insurance Program Reauthorization Act (MACRA) of 2015 requires the removal of the Social Security Number (SSN) from all Medicare cards. The primary goal of the law is to decrease Medicare beneficiaries’ vulnerability to identity theft. The Centers for Medicare & Medicaid Services (CMS) developed a new number called the Medicare Beneficiary Identifier (MBI), which replaces the SSN-based Health Insurance Claim Number (HICN) on the Medicare card.

CMS began mailing the new Medicare cards in April 2018. People with Medicare should start using their new Medicare cards right away.

B. The new Medicare Number

CMS issues all MBIs.

The Social Security Administration (SSA) and CMS will continue to transmit data electronically using the HICN. When communicating with beneficiaries, use the term “Medicare Number”. Avoid using the terms “HICN” and “MBI”.

New Medicare Numbers:

  • are unique to each beneficiary;

  • are not related to anyone else, like a spouse or number holder from which the beneficiary gets Social Security and Medicare entitlement;

  • no longer contain the beneficiary’s SSN;

  • do not impact a beneficiary’s Medicare coverage or benefits;

  • do not automatically change, regardless of changes to HICN, the Beneficiary Identification Code (BIC) or Claim Account Number (CAN);

  • are “non-intelligent” which means they don’t have any hidden or special meaning; and

  • are available by using the HI/SMI Query Response (HIQR).

  • The MBI is a random 11-digit alphanumeric code with the following values:

  • the first digit is a numeric value between 1 and 9;

  • the second, fifth, eighth, and ninth characters are alphabetic characters (A through Z) excluding (S, L, O, I, B, or Z);

  • the third and sixth digits are either alphabetic characters (A through Z) excluding (S, L, O, I, B, or Z) or numeric values between 0 and 9; and all alphabetic characters are uppercase only.

C. Changing the new MBI

A beneficiary’s Medicare Number stays the same even if Medicare entitlement, benefits, or Medicare Advantage or Part D enrollment changes. However, CMS will permit Medicare Number changes upon request. If a beneficiary suspects their MBI is compromised, the beneficiary can request to change their Medicare Number by calling 1-800-MEDICARE (1-800-633-4227). TTY users can call 1-877-486-2048. CMS can initiate a change to a beneficiary’s Medicare Number in limited situations, such as court order or other legal actions.

D. Processing beneficiary requests for a change of Medicare Number

CMS handles all requests for changes in Medicare Numbers, including Railroad Retirement Board beneficiaries. Advise the beneficiary to call Medicare 1-800-MEDICARE (1-800-633-4227) to request a new Medicare Number. TTY users can call 1-877-486-2048.

SSA technicians are to verify that the beneficiary’s mailing address is up-to-date. Process valid change of address (COA) requests to both the Title II and Title XVI records, as needed, following normal COA procedures.

In addition, advise the beneficiary “Medicare will never contact you to request personal information. Be sure to protect your Medicare Number like your SSN and only share it with trusted providers.”

E. Releasing the MBI over the telephone

We handle a telephone request for the Medicare Beneficiary Identifier (MBI) the same as we would a request for a Social Security number (SSN). Our procedures prohibit releasing the MBI over the telephone due to Personally Identifiable Information (PII) concerns put in place to protect the individual from potential fraudulent activities.

If an individual has a Medicare issue or concern with their MBI, advise the individual:

  • to contact Medicare at 1 800 MEDICARE (1-800-633-4227). TTY users can call 1-877-486-2048

  • or they can go online to and print out their Medicare Card

  • or they can also go to their account on In the iBeve tool, the MBI will appear in the Medicare entitlement section.

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HI 00901.040 - New Medicare Numbers and Number Change Requests - 01/31/2023
Batch run: 01/31/2023