| MAA | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MAB | Blue Cross Blue Shield Florida | https://www.floridablue.com/ |
| MAC | No Prefix Assigned | https://www.bcbs.com/member-services |
| MAE | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MAF | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MAG | Unknown Assignment | https://www.bcbs.com/ |
| MAH | Anthem Blue Cross Blue Shield Virginia | https://www.anthem.com/individual-and-family/health-insurance/virginia/ |
| MAI | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MAL | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MAM | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MAN | No Prefix Assigned | https://www.bcbs.com/member-services |
| MAO | Blue Cross Blue Shield Florida | https://www.floridablue.com/ |
| MAQ | Blue Cross Blue Shield Florida | https://www.floridablue.com/ |
| MAT | Blue Cross Blue Shield Texas | https://www.bcbstx.com/ |
| MAU | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MAV | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MAW | Anthem Blue Cross Blue Shield Connecticut | https://www.anthem.com/individual-and-family/health-insurance/connecticut/ |
| MAY | Blue Cross Blue Shield Nebraska | https://www.nebraskablue.com/ |
| MAZ | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MBA | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MBC | Blue Cross Blue Shield Tennessee | https://www.bcbst.com/get-insurance/index.page |
| MBD | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MBE | Blue Cross Blue Shield Nebraska | https://www.nebraskablue.com/ |
| MBF | Anthem Blue Cross Blue Shield Georgia | https://www.anthem.com/individual-and-family/health-insurance/georgia/ |
| MBG | Blue Cross Blue Shield Alabama | https://www.bcbsal.org/web/index.html |
| MBH | Blue Cross Blue Shield Alabama | https://www.bcbsal.org/web/index.html |
| MBJ | Regence | https://www.regence.com/member/home |
| MBK | Empire Blue Cross Blue Shield New York | https://www.empireblue.com/ |
| MBN | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MBO | Blue Cross Blue Shield Florida | https://www.floridablue.com/ |
| MBP | Anthem Blue Cross Blue Shield Indiana | https://www.anthem.com/individual-and-family/health-insurance/indiana/ |
| MBQ | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MBR | Anthem Blue Cross of California | https://www.anthem.com/ca/individual-and-family/health-insurance/california/ |
| MBS | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MBT | Anthem Blue Cross Blue Shield Missouri | https://www.anthem.com/individual-and-family/health-insurance/missouri/ |
| MBU | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MBV | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MBW | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MBX | No Prefix Assigned | https://www.bcbs.com/member-services |
| MBY | No Prefix Assigned | https://www.bcbs.com/member-services |
| MBZ | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MCA | Blue Shield of California | https://blueshieldcaplans.com/ |
| MCC | Blue Cross Blue Shield Texas | https://www.bcbstx.com/ |
| MCD | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MCF | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MCG | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MCH | Blue Cross Blue Shield Florida | https://www.floridablue.com/ |
| MCI | Anthem Blue Cross Blue Shield Georgia | https://www.anthem.com/individual-and-family/health-insurance/georgia/ |
| MCJ | Highmark Blue Cross Blue Shield | https://www.highmarkbcbswv.com/home/ |
| MCK | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MCL | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MCM | No Prefix Assigned | https://www.bcbs.com/member-services |
| MCP | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MCQ | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MCR | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MCS | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MCT | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MCU | No Prefix Assigned | https://www.bcbs.com/member-services |
| MCV | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MCW | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MCX | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MCY | Anthem Blue Cross Blue Shield Virginia | https://www.anthem.com/individual-and-family/health-insurance/virginia/ |
| MCZ | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MDA | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MDB | No Prefix Assigned | https://www.bcbs.com/member-services |
| MDC | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MDD | No Prefix Assigned | https://www.bcbs.com/member-services |
| MDE | Anthem Blue Cross of California | https://www.anthem.com/ca/individual-and-family/health-insurance/california/ |
| MDG | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MDI | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MDK | Blue Cross Blue Shield Arizona | https://www.azblue.com/individualsandfamilies |
| MDL | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MDM | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MDN | Anthem Blue Cross Blue Shield Wisconsin | https://www.anthem.com/individual-and-family/wisconsin/ |
| MDO | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MDQ | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MDR | Anthem Blue Cross Blue Shield Wisconsin | https://www.anthem.com/individual-and-family/wisconsin/ |
| MDS | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MDT | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MDU | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MDV | No Prefix Assigned | https://www.bcbs.com/member-services |
| MDW | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MDX | Blue Cross Blue Shield Alabama | https://www.bcbsal.org/web/index.html |
| MDY | Unknown Assignment | https://www.bcbs.com/ |
| MDZ | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MEA | Blue Shield of California | https://blueshieldcaplans.com/ |
| MEC | Anthem Blue Cross Blue Shield Virginia | https://www.anthem.com/individual-and-family/health-insurance/virginia/ |
| MED | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MEE | Anthem Blue Cross Blue Shield Virginia | https://www.anthem.com/individual-and-family/health-insurance/virginia/ |
| MEF | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MEH | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MEI | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MEJ | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MEK | Blue Shield of California | https://blueshieldcaplans.com/ |
| MEL | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MEN | Anthem Blue Cross Blue Shield Maine | https://www.anthem.com/individual-and-family/health-insurance/maine/ |
| MEO | Blue Shield of California | https://blueshieldcaplans.com/ |
| MEP | Anthem Blue Cross Blue Shield Maine | https://www.anthem.com/individual-and-family/health-insurance/maine/ |
| MEQ | Blue Shield of California | https://blueshieldcaplans.com/ |
| MER | Anthem Blue Cross Blue Shield Wisconsin | https://www.anthem.com/individual-and-family/wisconsin/ |
| MES | Blue Cross Blue Shield Oklahoma | https://www.bcbsok.com/ |
| MET | Blue Cross Blue Shield Nebraska | https://www.nebraskablue.com/ |
| MEV | No Prefix Assigned | https://www.bcbs.com/member-services |
| MEX | Unknown Assignment | https://www.bcbs.com/ |
| MEZ | Unknown Assignment | https://www.bcbs.com/ |
| MFA | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MFB | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MFC | Anthem Blue Cross Blue Shield Georgia | https://www.anthem.com/individual-and-family/health-insurance/georgia/ |
| MFE | Anthem Blue Cross of California | https://www.anthem.com/ca/individual-and-family/health-insurance/california/ |
| MFG | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MFI | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MFK | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MFL | Independence Blue Cross | https://www.ibx.com/index.jsp |
| MFN | Anthem Blue Cross Blue Shield Virginia | https://www.anthem.com/individual-and-family/health-insurance/virginia/ |
| MFQ | Anthem Blue Cross Blue Shield Virginia | https://www.anthem.com/individual-and-family/health-insurance/virginia/ |
| MFR | No Prefix Assigned | https://www.bcbs.com/member-services |
| MFS | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MFT | No Prefix Assigned | https://www.bcbs.com/member-services |
| MFU | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MFV | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MFW | Anthem Blue Cross of California | https://www.anthem.com/ca/individual-and-family/health-insurance/california/ |
| MFY | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MFZ | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MGA | Blue Shield of California | https://blueshieldcaplans.com/ |
| MGB | Capital Blue Cross | https://www.capbluecross.com/ |
| MGD | Premera Blue Cross | https://www.premera.com/visitor |
| MGE | Blue Cross Blue Shield Rhode Island | https://www.bcbsri.com/ |
| MGF | No Prefix Assigned | https://www.bcbs.com/member-services |
| MGG | Blue Shield of California | https://blueshieldcaplans.com/ |
| MGH | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MGK | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MGL | Independence Blue Cross | https://www.ibx.com/index.jsp |
| MGM | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MGO | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MGP | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MGQ | No Prefix Assigned | https://www.bcbs.com/member-services |
| MGR | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MGS | Anthem Blue Cross Blue Shield Georgia | https://www.anthem.com/individual-and-family/health-insurance/georgia/ |
| MGU | Anthem Blue Cross Blue Shield Virginia | https://www.anthem.com/individual-and-family/health-insurance/virginia/ |
| MGV | Blue Cross Blue Shield South Carolina | https://www.southcarolinablues.com/web/public/brands/sc/ |
| MGX | No Prefix Assigned | https://www.bcbs.com/member-services |
| MGY | Blue Shield of California | https://blueshieldcaplans.com/ |
| MGZ | Horizon Blue Cross Blue Shield New Jersey | https://www.horizonblue.com/ |
| MHA | Unknown Assignment | https://www.bcbs.com/ |
| MHB | Blue Cross Blue Shield Texas | https://www.bcbstx.com/ |
| MHC | Highmark Blue Cross Blue Shield | https://www.highmarkblueshield.com/home/ |
| MHD | No Prefix Assigned | https://www.bcbs.com/member-services |
| MHF | No Prefix Assigned | https://www.bcbs.com/member-services |
| MHH | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MHJ | No Prefix Assigned | https://www.bcbs.com/member-services |
| MHK | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MHL | Unknown Assignment | https://www.bcbs.com/ |
| MHM | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MHN | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MHS | No Prefix Assigned | https://www.bcbs.com/member-services |
| MHT | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MHU | No Prefix Assigned | https://www.bcbs.com/member-services |
| MHV | No Prefix Assigned | https://www.bcbs.com/member-services |
| MHW | Blue Cross Blue Shield Alabama | https://www.bcbsal.org/web/index.html |
| MHX | No Prefix Assigned | https://www.bcbs.com/member-services |
| MHY | Anthem Blue Cross of California | https://www.anthem.com/ca/individual-and-family/health-insurance/california/ |
| MHZ | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MIB | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MIC | Blue Cross Blue Shield South Carolina | https://www.southcarolinablues.com/web/public/brands/sc/ |
| MID | No Prefix Assigned | https://www.bcbs.com/member-services |
| MIE | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MIF | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MIG | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MIH | Anthem Blue Cross Blue Shield Georgia | https://www.anthem.com/individual-and-family/health-insurance/georgia/ |
| MII | Unknown Assignment | https://www.bcbs.com/ |
| MIJ | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MIK | Capital Blue Cross | https://www.capbluecross.com/ |
| MIM | Highmark Blue Cross Blue Shield | https://www.highmarkbcbs.com/home/ |
| MIO | Blue Shield of California | https://blueshieldcaplans.com/ |
| MIP | Blue Cross of Idaho | https://www.bcidaho.com/ |
| MIQ | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MIR | No Prefix Assigned | https://www.bcbs.com/member-services |
| MIS | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MIT | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MIU | Blue Cross Blue Shield South Carolina | https://www.southcarolinablues.com/web/public/brands/sc/ |
| MIV | Blue Cross Blue Shield Western New York | https://www.bcbswny.com/ |
| MIW | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MIX | Blue Shield of California | https://blueshieldcaplans.com/ |
| MIY | No Prefix Assigned | https://www.bcbs.com/member-services |
| MIZ | Blue Shield of California | https://blueshieldcaplans.com/ |
| MJA | Blue Cross Blue Shield Western New York | https://www.bcbswny.com/ |
| MJD | Blue Cross Blue Shield Alabama | https://www.bcbsal.org/web/index.html |
| MJE | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MJF | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MJG | Premera Blue Cross | https://www.premera.com/visitor |
| MJI | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MJJ | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MJL | Anthem Blue Cross of California | https://www.anthem.com/ca/individual-and-family/health-insurance/california/ |
| MJM | Highmark Blue Cross Blue Shield | https://www.highmarkbcbs.com/home/ |
| MJN | Highmark Blue Cross Blue Shield | https://www.highmarkbcbs.com/home/ |
| MJP | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MJR | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MJS | Blue Cross Blue Shield Tennessee | https://www.bcbst.com/get-insurance/index.page |
| MJT | Anthem Blue Cross Blue Shield Wisconsin | https://www.anthem.com/individual-and-family/wisconsin/ |
| MJU | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MJW | No Prefix Assigned | https://www.bcbs.com/member-services |
| MJX | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MJY | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MJZ | No Prefix Assigned | https://www.bcbs.com/member-services |
| MKA | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MKB | Blue Shield of California | https://blueshieldcaplans.com/ |
| MKC | Blue Cross Blue Shield South Carolina | https://www.southcarolinablues.com/web/public/brands/sc/ |
| MKD | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MKE | Blue Cross Blue Shield Tennessee | https://www.bcbst.com/get-insurance/index.page |
| MKF | No Prefix Assigned | https://www.bcbs.com/member-services |
| MKG | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MKH | Blue Cross Blue Shield Tennessee | https://www.bcbst.com/get-insurance/index.page |
| MKI | Blue Cross Blue Shield Tennessee | https://www.bcbst.com/get-insurance/index.page |
| MKJ | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MKK | Anthem Blue Cross of California | https://www.anthem.com/ca/individual-and-family/health-insurance/california/ |
| MKL | Blue Cross Blue Shield Mississippi | https://www.bcbsms.com/ |
| MKM | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MKN | No Prefix Assigned | https://www.bcbs.com/member-services |
| MKO | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MKP | No Prefix Assigned | https://www.bcbs.com/member-services |
| MKQ | No Prefix Assigned | https://www.bcbs.com/member-services |
| MKS | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MKT | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MKU | Premera Blue Cross | https://www.premera.com/visitor |
| MKV | Horizon Blue Cross Blue Shield New Jersey | https://www.horizonblue.com/ |
| MKW | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MKX | No Prefix Assigned | https://www.bcbs.com/member-services |
| MKY | Horizon Blue Cross Blue Shield New Jersey | https://www.horizonblue.com/ |
| MKZ | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MLA | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MLC | No Prefix Assigned | https://www.bcbs.com/member-services |
| MLE | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MLG | Highmark Blue Cross Blue Shield | https://www.highmarkblueshield.com/home/ |
| MLH | No Prefix Assigned | https://www.bcbs.com/member-services |
| MLJ | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MLK | Anthem Blue Cross Blue Shield Virginia | https://www.anthem.com/individual-and-family/health-insurance/virginia/ |
| MLL | Blue Shield of California | https://blueshieldcaplans.com/ |
| MLM | Highmark Blue Cross Blue Shield | https://www.highmarkbcbs.com/home/ |
| MLN | Blue Shield of California | https://blueshieldcaplans.com/ |
| MLO | Blue Cross Blue Shield Western New York | https://www.bcbswny.com/ |
| MLP | Anthem Blue Cross Blue Shield Virginia | https://www.anthem.com/individual-and-family/health-insurance/virginia/ |
| MLQ | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MLS | Blue Cross Blue Shield Alabama | https://www.bcbsal.org/web/index.html |
| MLT | Blue Cross Blue Shield Nebraska | https://www.nebraskablue.com/ |
| MLU | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MLV | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MLW | No Prefix Assigned | https://www.bcbs.com/member-services |
| MLX | No Prefix Assigned | https://www.bcbs.com/member-services |
| MLY | Premera Blue Cross | https://www.premera.com/visitor |
| MLZ | Blue Cross Blue Shield Rhode Island | https://www.bcbsri.com/ |
| MMB | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MMD | Premera Blue Cross | https://www.premera.com/visitor |
| MMF | Excellus Blue Cross Blue Shield New York | https://www.excellusbcbs.com/ |
| MMG | Blue Cross Blue Shield Mississippi | https://www.bcbsms.com/ |
| MMH | Empire Blue Cross Blue Shield New York | https://www.empireblue.com/ |
| MMI | Independence Blue Cross | https://www.ibx.com/index.jsp |
| MMJ | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MMK | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MMM | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MMN | Blue Cross Blue Shield Tennessee | https://www.bcbst.com/get-insurance/index.page |
| MMO | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MMP | Blue Cross Blue Shield North Carolina | https://www.bluecrossnc.com/ |
| MMQ | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MMS | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MMT | No Prefix Assigned | https://www.bcbs.com/member-services |
| MMU | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MMV | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MMW | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MMX | Blue Cross Blue Shield Alabama | https://www.bcbsal.org/web/index.html |
| MMZ | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MNA | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MNB | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MNC | Anthem Blue Cross of California | https://www.anthem.com/ca/individual-and-family/health-insurance/california/ |
| MND | Anthem Blue Cross Blue Shield Wisconsin | https://www.anthem.com/individual-and-family/wisconsin/ |
| MNE | Anthem Blue Cross Blue Shield Wisconsin | https://www.anthem.com/individual-and-family/wisconsin/ |
| MNF | Independence Blue Cross | https://www.ibx.com/index.jsp |
| MNG | Blue Cross Blue Shield Tennessee | https://www.bcbst.com/get-insurance/index.page |
| MNH | Anthem Blue Cross Blue Shield Virginia | https://www.anthem.com/individual-and-family/health-insurance/virginia/ |
| MNI | No Prefix Assigned | https://www.bcbs.com/member-services |
| MNK | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MNL | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MNM | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MNN | Highmark Blue Cross Blue Shield | https://www.highmarkbcbs.com/home/ |
| MNO | Blue Cross Blue Shield North Carolina | https://www.bluecrossnc.com/ |
| MNP | Blue Shield of California | https://blueshieldcaplans.com/ |
| MNQ | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MNR | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MNS | Anthem Blue Cross Blue Shield Kentucky | https://www.anthem.com/individual-and-family/health-insurance/kentucky/ |
| MNT | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MNU | Blue Cross Blue Shield North Carolina | https://www.bluecrossnc.com/ |
| MNW | Premera Blue Cross | https://www.premera.com/visitor |
| MNX | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MNZ | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MOA | No Prefix Assigned | https://www.bcbs.com/member-services |
| MOC | Anthem Blue Cross Blue Shield Georgia | https://www.anthem.com/individual-and-family/health-insurance/georgia/ |
| MOD | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MOE | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MOF | Blue Shield of California | https://blueshieldcaplans.com/ |
| MOG | Blue Cross Blue Shield Western New York | https://www.bcbswny.com/ |
| MOH | No Prefix Assigned | https://www.bcbs.com/member-services |
| MOI | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MOJ | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MOK | Independence Blue Cross | https://www.ibx.com/index.jsp |
| MOL | No Prefix Assigned | https://www.bcbs.com/member-services |
| MOM | No Prefix Assigned | https://www.bcbs.com/member-services |
| MOR | Premera Blue Cross | https://www.premera.com/visitor |
| MOT | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MOW | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MOX | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MOY | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MPA | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MPC | Blue Cross Blue Shield Rhode Island | https://www.bcbsri.com/ |
| MPD | Blue Cross Blue Shield Texas | https://www.bcbstx.com/ |
| MPE | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MPF | Excellus Blue Cross Blue Shield New York | https://www.excellusbcbs.com/ |
| MPH | Empire Blue Cross Blue Shield New York | https://www.empireblue.com/ |
| MPI | Anthem Blue Cross of California | https://www.anthem.com/ca/individual-and-family/health-insurance/california/ |
| MPL | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MPM | No Prefix Assigned | https://www.bcbs.com/member-services |
| MPO | Blue Cross Blue Shield Alabama | https://www.bcbsal.org/web/index.html |
| MPP | Anthem Blue Cross Blue Shield Wisconsin | https://www.anthem.com/individual-and-family/wisconsin/ |
| MPQ | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MPR | Anthem Blue Cross of California | https://www.anthem.com/ca/individual-and-family/health-insurance/california/ |
| MPS | Anthem Blue Cross Blue Shield Georgia | https://www.anthem.com/individual-and-family/health-insurance/georgia/ |
| MPT | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MPU | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MPV | No Prefix Assigned | https://www.bcbs.com/member-services |
| MPW | No Prefix Assigned | https://www.bcbs.com/member-services |
| MPX | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MQA | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MQC | Anthem Blue Cross of California | https://www.anthem.com/ca/individual-and-family/health-insurance/california/ |
| MQD | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MQF | Blue Cross Blue Shield Western New York | https://www.bcbswny.com/ |
| MQH | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MQI | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MQJ | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MQK | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MQL | Anthem Blue Cross Blue Shield Georgia | https://www.anthem.com/individual-and-family/health-insurance/georgia/ |
| MQM | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MQN | Blue Cross Blue Shield North Carolina | https://www.bluecrossnc.com/ |
| MQO | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MQP | Anthem Blue Cross of California | https://www.anthem.com/ca/individual-and-family/health-insurance/california/ |
| MQR | Highmark Blue Cross Blue Shield | https://www.highmarkblueshield.com/home/ |
| MQS | No Prefix Assigned | https://www.bcbs.com/member-services |
| MQT | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MQU | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MQW | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MQX | Anthem Blue Cross of California | https://www.anthem.com/ca/individual-and-family/health-insurance/california/ |
| MQY | Blue Cross Blue Shield North Carolina | https://www.bluecrossnc.com/ |
| MQZ | Anthem Blue Cross of California | https://www.anthem.com/ca/individual-and-family/health-insurance/california/ |
| MRA | No Prefix Assigned | https://www.bcbs.com/member-services |
| MRC | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MRE | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MRF | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MRG | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MRJ | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MRM | Unknown Assignment | https://www.bcbs.com/ |
| MRN | Anthem Blue Cross Blue Shield Wisconsin | https://www.anthem.com/individual-and-family/wisconsin/ |
| MRO | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MRP | Anthem Blue Cross Blue Shield Wisconsin | https://www.anthem.com/individual-and-family/wisconsin/ |
| MRQ | No Prefix Assigned | https://www.bcbs.com/member-services |
| MRR | No Prefix Assigned | https://www.bcbs.com/member-services |
| MRS | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MRT | Blue Cross Blue Shield Texas | https://www.bcbstx.com/ |
| MRU | Highmark Blue Cross Blue Shield | https://www.highmarkbcbs.com/home/ |
| MRV | Anthem Blue Cross of California | https://www.anthem.com/ca/individual-and-family/health-insurance/california/ |
| MRW | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MRY | Blue Cross Blue Shield Alabama | https://www.bcbsal.org/web/index.html |
| MRZ | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MSA | Blue Cross Blue Shield Alabama | https://www.bcbsal.org/web/index.html |
| MSB | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MSC | Blue Cross Blue Shield Alabama | https://www.bcbsal.org/web/index.html |
| MSF | Empire Blue Cross Blue Shield New York | https://www.empireblue.com/ |
| MSG | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MSH | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MSJ | Premera Blue Cross | https://www.premera.com/visitor |
| MSK | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MSL | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MSM | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MSO | No Prefix Assigned | https://www.bcbs.com/member-services |
| MSP | Premera Blue Cross | https://www.premera.com/visitor |
| MSQ | Premera Blue Cross | https://www.premera.com/visitor |
| MSR | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MSS | Anthem Blue Cross Blue Shield Virginia | https://www.anthem.com/individual-and-family/health-insurance/virginia/ |
| MST | Premera Blue Cross | https://www.premera.com/visitor |
| MSU | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MSV | Blue Cross Blue Shield Alabama | https://www.bcbsal.org/web/index.html |
| MSW | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MSX | Anthem Blue Cross of California | https://www.anthem.com/ca/individual-and-family/health-insurance/california/ |
| MSY | No Prefix Assigned | https://www.bcbs.com/member-services |
| MSZ | Anthem Blue Cross of California | https://www.anthem.com/ca/individual-and-family/health-insurance/california/ |
| MTB | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MTC | Anthem Blue Cross Blue Shield Virginia | https://www.anthem.com/individual-and-family/health-insurance/virginia/ |
| MTD | Premera Blue Cross | https://www.premera.com/visitor |
| MTE | Blue Shield of California | https://blueshieldcaplans.com/ |
| MTG | No Prefix Assigned | https://www.bcbs.com/member-services |
| MTH | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MTI | No Prefix Assigned | https://www.bcbs.com/member-services |
| MTJ | Blue Cross of Idaho | https://www.bcidaho.com/ |
| MTK | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MTL | Blue Cross Blue Shield Texas | https://www.bcbstx.com/ |
| MTM | Blue Cross Blue Shield Western New York | https://www.bcbswny.com/ |
| MTN | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MTP | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MTQ | Blue Shield of California | https://blueshieldcaplans.com/ |
| MTR | Blue Cross Blue Shield Tennessee | https://www.bcbst.com/get-insurance/index.page |
| MTS | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MTT | Blue Shield of California | https://blueshieldcaplans.com/ |
| MTU | Premera Blue Cross | https://www.premera.com/visitor |
| MTX | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MTY | Anthem Blue Cross of California | https://www.anthem.com/ca/individual-and-family/health-insurance/california/ |
| MTZ | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MUA | Blue Cross Blue Shield Texas | https://www.bcbstx.com/ |
| MUB | Anthem Blue Cross Blue Shield Virginia | https://www.anthem.com/individual-and-family/health-insurance/virginia/ |
| MUC | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MUD | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MUE | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MUH | Blue Cross of Idaho | https://www.bcidaho.com/ |
| MUJ | Anthem Blue Cross Blue Shield Georgia | https://www.anthem.com/individual-and-family/health-insurance/georgia/ |
| MUL | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MUM | Blue Cross Blue Shield Arizona | https://www.azblue.com/individualsandfamilies |
| MUN | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MUP | Blue Cross Blue Shield South Carolina | https://www.southcarolinablues.com/web/public/brands/sc/ |
| MUR | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MUS | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MUU | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MUV | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MUW | Highmark Blue Cross Blue Shield | https://www.highmarkbcbs.com/home/ |
| MUX | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MUY | Blue Cross Blue Shield Alabama | https://www.bcbsal.org/web/index.html |
| MUZ | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MVA | Blue Cross Blue Shield Montana | https://www.bcbsmt.com/ |
| MVC | Blue Cross Blue Shield Florida | https://www.floridablue.com/ |
| MVD | Premera Blue Cross | https://www.premera.com/visitor |
| MVF | Empire Blue Cross Blue Shield New York | https://www.empireblue.com/ |
| MVG | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MVH | No Prefix Assigned | https://www.bcbs.com/member-services |
| MVI | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MVJ | Blue Shield of California | https://blueshieldcaplans.com/ |
| MVK | Anthem Blue Cross Blue Shield Georgia | https://www.anthem.com/individual-and-family/health-insurance/georgia/ |
| MVL | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MVM | Blue Cross Blue Shield Alabama | https://www.bcbsal.org/web/index.html |
| MVN | Empire Blue Cross Blue Shield New York | https://www.empireblue.com/ |
| MVO | No Prefix Assigned | https://www.bcbs.com/member-services |
| MVR | Highmark Blue Cross Blue Shield | https://www.highmarkblueshield.com/home/ |
| MVS | No Prefix Assigned | https://www.bcbs.com/member-services |
| MVT | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MVU | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MVV | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MVX | Blue Cross Blue Shield South Carolina | https://www.southcarolinablues.com/web/public/brands/sc/ |
| MVY | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MVZ | No Prefix Assigned | https://www.bcbs.com/member-services |
| MWA | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MWB | No Prefix Assigned | https://www.bcbs.com/member-services |
| MWD | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MWE | Anthem Blue Cross Blue Shield Wisconsin | https://www.anthem.com/individual-and-family/wisconsin/ |
| MWF | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MWG | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MWI | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MWJ | Horizon Blue Cross Blue Shield New Jersey | https://www.horizonblue.com/ |
| MWK | Horizon Blue Cross Blue Shield New Jersey | https://www.horizonblue.com/ |
| MWL | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MWM | Anthem Blue Cross Blue Shield Wisconsin | https://www.anthem.com/individual-and-family/wisconsin/ |
| MWN | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MWQ | No Prefix Assigned | https://www.bcbs.com/member-services |
| MWR | Unknown Assignment | https://www.bcbs.com/ |
| MWS | No Prefix Assigned | https://www.bcbs.com/member-services |
| MWU | Anthem Blue Cross Blue Shield Wisconsin | https://www.anthem.com/individual-and-family/wisconsin/ |
| MWV | Anthem Blue Cross Blue Shield Wisconsin | https://www.anthem.com/individual-and-family/wisconsin/ |
| MWW | Anthem Blue Cross Blue Shield Nevada | https://www.anthem.com/individual-and-family/health-insurance/nevada/ |
| MWX | Blue Cross Blue Shield Alabama | https://www.bcbsal.org/web/index.html |
| MWY | No Prefix Assigned | https://www.bcbs.com/member-services |
| MXA | Anthem Blue Cross of California | https://www.anthem.com/ca/individual-and-family/health-insurance/california/ |
| MXB | Highmark Blue Cross Blue Shield | https://www.highmarkbcbs.com/home/ |
| MXC | No Prefix Assigned | https://www.bcbs.com/member-services |
| MXD | Blue Cross Blue Shield Texas | https://www.bcbstx.com/ |
| MXE | Blue Cross Blue Shield Texas | https://www.bcbstx.com/ |
| MXF | Empire Blue Cross Blue Shield New York | https://www.empireblue.com/ |
| MXH | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MXI | Blue Shield of California | https://blueshieldcaplans.com/ |
| MXJ | No Prefix Assigned | https://www.bcbs.com/member-services |
| MXK | Capital Blue Cross | https://www.capbluecross.com/ |
| MXM | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MXN | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MXO | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MXP | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MXQ | Empire Blue Cross Blue Shield New York | https://www.empireblue.com/ |
| MXR | Anthem Blue Cross of California | https://www.anthem.com/ca/individual-and-family/health-insurance/california/ |
| MXS | Anthem Blue Cross Blue Shield Georgia | https://www.anthem.com/individual-and-family/health-insurance/georgia/ |
| MXT | No Prefix Assigned | https://www.bcbs.com/member-services |
| MXX | No Prefix Assigned | https://www.bcbs.com/member-services |
| MXY | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MXZ | Premera Blue Cross | https://www.premera.com/visitor |
| MYA | Independence Blue Cross | https://www.ibx.com/index.jsp |
| MYC | No Prefix Assigned | https://www.bcbs.com/member-services |
| MYD | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MYE | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MYF | Empire Blue Cross Blue Shield New York | https://www.empireblue.com/ |
| MYG | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MYH | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MYI | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MYJ | No Prefix Assigned | https://www.bcbs.com/member-services |
| MYK | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MYL | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MYM | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MYN | Anthem Blue Cross Blue Shield Ohio | https://www.anthem.com/individual-and-family/health-insurance/ohio |
| MYO | No Prefix Assigned | https://www.bcbs.com/member-services |
| MYP | Anthem Blue Cross Blue Shield Georgia | https://www.anthem.com/individual-and-family/health-insurance/georgia/ |
| MYQ | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MYR | Blue Cross Blue Shield Alabama | https://www.bcbsal.org/web/index.html |
| MYS | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MYT | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MYV | No Prefix Assigned | https://www.bcbs.com/member-services |
| MYW | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MYX | Blue Cross Blue Shield Oklahoma | https://www.bcbsok.com/ |
| MYY | Carefirst Blue Cross Blue Shield Maryland | https://individual.carefirst.com/individuals-families/home.page |
| MYZ | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MZA | Wellmark Blue Cross Blue Shield | https://www.wellmark.com/ |
| MZB | Highmark Blue Cross Blue Shield | https://www.highmarkbcbs.com/home/ |
| MZC | Blue Cross Blue Shield Rhode Island | https://www.bcbsri.com/ |
| MZD | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MZE | Blue Cross Blue Shield Massachusetts | https://home.bluecrossma.com/ |
| MZF | No Prefix Assigned | https://www.bcbs.com/member-services |
| MZG | Blue Cross Blue Shield Illinois | https://www.bcbsil.com/ |
| MZJ | Anthem Blue Cross Blue Shield Wisconsin | https://www.anthem.com/individual-and-family/wisconsin/ |
| MZL | Blue Cross Blue Shield Alabama | https://www.bcbsal.org/web/index.html |
| MZM | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MZN | Blue Cross Blue Shield North Carolina | https://www.bluecrossnc.com/ |
| MZO | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MZP | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MZS | Blue Cross Blue Shield North Carolina | https://www.bluecrossnc.com/ |
| MZT | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MZU | Blue Cross Blue Shield Florida | https://www.floridablue.com/ |
| MZV | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MZX | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |
| MZY | Blue Cross Blue Shield Michigan | https://www.bcbsm.com/ |
| MZZ | Blue Cross Blue Shield Minnesota | https://www.bluecrossmn.com/ |