| OAA | - | Unallocated/Not Assigned |
| OAB | Massachusetts | Blue-Cross Blue-Shield of Massachusetts |
| OAC | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| OAD | New York (Western) | Blue-Cross Blue-Shield of Western New York |
| OAE | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| OAF | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| OAG | Colorado | Anthem Blue-Cross Blue-Shield of Colorado |
| OAH | New York | Empire Blue-Cross Blue-Shield of New York |
| OAI | California | Blue-Shield of California |
| OAJ | - | Unallocated/Not Assigned |
| OAK | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| OAL | California | Blue-Shield of California |
| OAM | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| OAN | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OAO | - | Unallocated/Not Assigned |
| OAP | Kentucky | Anthem Blue-Cross Blue-Shield of Kentucky |
| OAQ | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OAR | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OAS | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| OAT | Nebraska | Blue-Cross Blue-Shield of Nebraska |
| OAU | Michigan | Blue-Cross Blue-Shield of Michigan |
| OAV | - | Unallocated/Not Assigned |
| OAW | - | Unallocated/Not Assigned |
| OAX | - | Unallocated/Not Assigned |
| OAY | - | Unallocated/Not Assigned |
| OAZ | Massachusetts | Blue-Cross Blue-Shield of Massachusetts |
| OBA | California | Anthem Blue-Cross |
| OBB | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| OBC | Massachusetts | Blue-Cross Blue-Shield of Massachusetts |
| OBD | Florida | Florida-Blue |
| OBE | Michigan | Blue-Cross Blue-Shield of Michigan |
| OBF | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| OBG | - | Unallocated/Not Assigned |
| OBH | - | Unallocated/Not Assigned |
| OBI | Minnesota | Blue-Cross Blue-Shield of Minnesota |
| OBJ | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| OBK | - | Unallocated/Not Assigned |
| OBL | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OBM | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OBN | Massachusetts | Blue-Cross Blue-Shield of Massachusetts |
| OBO | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| OBP | California | Blue-Shield of California |
| OBQ | California | Anthem Blue-Cross |
| OBR | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OBS | - | Unallocated/Not Assigned |
| OBT | Arizona | Blue-Cross Blue-Shield of Arizona |
| OBU | Alabama | Blue-Cross Blue-Shield of Alabama |
| OBV | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| OBW | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| OBX | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| OBY | - | Unallocated/Not Assigned |
| OBZ | - | Unallocated/Not Assigned |
| OCA | California | Anthem Blue-Cross |
| OCB | - | Unallocated/Not Assigned |
| OCC | - | Unallocated/Not Assigned |
| OCD | California | Blue-Shield of California |
| OCE | - | Unallocated/Not Assigned |
| OCF | Louisiana | Blue-Cross Blue-Shield of Louisiana |
| OCG | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OCH | New York (Western) | Blue-Cross Blue-Shield of Western New York |
| OCI | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| OCJ | - | Unallocated/Not Assigned |
| OCK | Florida | Florida-Blue |
| OCL | - | Unallocated/Not Assigned |
| OCM | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OCN | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| OCO | California | Blue-Shield of California |
| OCP | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| OCQ | - | Unallocated/Not Assigned |
| OCR | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| OCS | - | Unallocated/Not Assigned |
| OCT | Idaho | Blue-Cross of Idaho |
| OCU | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| OCV | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OCW | California | Anthem Blue-Cross |
| OCX | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OCY | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OCZ | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| ODA | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| ODB | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| ODC | - | Unallocated/Not Assigned |
| ODD | - | Unallocated/Not Assigned |
| ODE | - | Unallocated/Not Assigned |
| ODF | Massachusetts | Blue-Cross Blue-Shield of Massachusetts |
| ODG | - | Unallocated/Not Assigned |
| ODH | - | Unallocated/Not Assigned |
| ODI | New York (Western) | Blue-Cross Blue-Shield of Western New York |
| ODJ | Tennessee | Blue-Cross Blue-Shield of Tennessee |
| ODK | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| ODL | Tennessee | Blue-Cross Blue-Shield of Tennessee |
| ODM | Arizona | Blue-Cross Blue-Shield of Arizona |
| ODN | Tennessee | Blue-Cross Blue-Shield of Tennessee |
| ODO | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| ODP | - | Unallocated/Not Assigned |
| ODQ | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| ODR | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| ODS | New York (Western) | Blue-Cross Blue-Shield of Western New York |
| ODT | Massachusetts | Blue-Cross Blue-Shield of Massachusetts |
| ODU | - | Unallocated/Not Assigned |
| ODV | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| ODW | Michigan | Blue-Cross Blue-Shield of Michigan |
| ODX | Alabama | Blue-Cross Blue-Shield of Alabama |
| ODY | Michigan | Blue-Cross Blue-Shield of Michigan |
| ODZ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OEA | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| OEB | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| OEC | - | Unallocated/Not Assigned |
| OED | - | Unallocated/Not Assigned |
| OEE | Florida | Florida-Blue |
| OEF | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OEG | Kansas City | Blue-Cross Blue-Shield of Kansas City |
| OEH | California | Anthem Blue-Cross |
| OEI | Nebraska | Blue-Cross Blue-Shield of Nebraska |
| OEJ | California | Blue-Shield of California |
| OEK | Michigan | Blue-Cross Blue-Shield of Michigan |
| OEL | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OEM | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| OEN | - | Unallocated/Not Assigned |
| OEO | - | Unallocated/Not Assigned |
| OEP | - | Unallocated/Not Assigned |
| OEQ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OER | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| OES | California | Anthem Blue-Cross |
| OET | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OEU | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| OEV | Pennsylvania | Highmark Blue-Shield of Pennsylvania |
| OEW | North Dakota | Blue-Cross Blue-Shield of North Dakota |
| OEX | - | Unallocated/Not Assigned |
| OEY | Michigan | Blue-Cross Blue-Shield of Michigan |
| OEZ | South Carolina | Blue-Cross Blue-Shield of South Carolina |
| OFA | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| OFB | Pennsylvania | Capital Blue-Cross of Pennsylvania |
| OFC | Michigan | Blue-Cross Blue-Shield of Michigan |
| OFD | - | Unallocated/Not Assigned |
| OFE | - | Unallocated/Not Assigned |
| OFF | New York (Western) | Blue-Cross Blue-Shield of Western New York |
| OFG | Rhode Island | Blue-Cross Blue-Shield of Rhode Island |
| OFH | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| OFI | - | Unallocated/Not Assigned |
| OFJ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OFK | - | Unallocated/Not Assigned |
| OFL | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OFM | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OFN | Tennessee | Blue-Cross Blue-Shield of Tennessee |
| OFO | California | Anthem Blue-Cross |
| OFP | California | Anthem Blue-Cross |
| OFQ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OFR | - | Unallocated/Not Assigned |
| OFS | New York (Western) | Blue-Cross Blue-Shield of Western New York |
| OFT | California | Blue-Shield of California |
| OFU | Michigan | Blue-Cross Blue-Shield of Michigan |
| OFV | Michigan | Blue-Cross Blue-Shield of Michigan |
| OFW | Michigan | Blue-Cross Blue-Shield of Michigan |
| OFX | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| OFY | California | Blue-Shield of California |
| OFZ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OGA | - | Unallocated/Not Assigned |
| OGB | - | Unallocated/Not Assigned |
| OGC | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OGD | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| OGE | - | Unallocated/Not Assigned |
| OGF | Michigan | Blue-Cross Blue-Shield of Michigan |
| OGG | - | Unallocated/Not Assigned |
| OGH | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| OGI | - | Unallocated/Not Assigned |
| OGJ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OGK | Michigan | Blue-Cross Blue-Shield of Michigan |
| OGL | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OGM | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| OGN | Kentucky | Anthem Blue-Cross Blue-Shield of Kentucky |
| OGO | Michigan | Blue-Cross Blue-Shield of Michigan |
| OGP | - | Unallocated/Not Assigned |
| OGQ | - | Unallocated/Not Assigned |
| OGR | - | Unallocated/Not Assigned |
| OGS BCBS Prefix | Louisiana | Blue-Cross Blue-Shield of Louisiana |
| OGT | New York (Western) | Blue-Cross Blue-Shield of Western New York |
| OGU | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| OGV | - | Unallocated/Not Assigned |
| OGW | Louisiana | Blue-Cross Blue-Shield of Louisiana |
| OGX | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OGY | - | Unallocated/Not Assigned |
| OGZ | - | Unallocated/Not Assigned |
| OHA | South Carolina | Blue-Cross Blue-Shield of South Carolina |
| OHB | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| OHC | Michigan | Blue-Cross Blue-Shield of Michigan |
| OHD | Texas | Blue-Cross Blue-Shield of Texas |
| OHE | Rhode Island | Blue-Cross Blue-Shield of Rhode Island |
| OHF | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| OHG | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| OHH | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| OHI | Louisiana | Blue-Cross Blue-Shield of Louisiana |
| OHJ | Kentucky | Anthem Blue-Cross Blue-Shield of Kentucky |
| OHK | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OHL | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| OHM | New York (Northeastern) | Blue-Shield of Northeastern New York |
| OHN | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OHO | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| OHP | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| OHQ | - | Unallocated/Not Assigned |
| OHR | Colorado | Anthem Blue-Cross Blue-Shield of Colorado |
| OHS | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| OHT | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| OHU | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OHV | Rhode Island | Blue-Cross Blue-Shield of Rhode Island |
| OHW | - | Unallocated/Not Assigned |
| OHX | Rhode Island | Blue-Cross Blue-Shield of Rhode Island |
| OHY | Michigan | Blue-Cross Blue-Shield of Michigan |
| OHZ | Rhode Island | Blue-Cross Blue-Shield of Rhode Island |
| OIA | - | Unallocated/Not Assigned |
| OIB | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| OIC | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| OID | Idaho | Blue-Cross of Idaho |
| OIE | - | Unallocated/Not Assigned |
| OIF | - | Unallocated/Not Assigned |
| OIG | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| OIH | - | Unallocated/Not Assigned |
| OII | Michigan | Blue-Cross Blue-Shield of Michigan |
| OIJ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OIK | Michigan | Blue-Cross Blue-Shield of Michigan |
| OIL | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| OIM | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| OIN | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| OIO | Michigan | Blue-Cross Blue-Shield of Michigan |
| OIP | California | Blue-Shield of California |
| OIQ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OIR | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| OIS | New York (Western) | Blue-Cross Blue-Shield of Western New York |
| OIT | Michigan | Blue-Cross Blue-Shield of Michigan |
| OIU | Michigan | Blue-Cross Blue-Shield of Michigan |
| OIV | Michigan | Blue-Cross Blue-Shield of Michigan |
| OIW | Michigan | Blue-Cross Blue-Shield of Michigan |
| OIX | Michigan | Blue-Cross Blue-Shield of Michigan |
| OIY | Michigan | Blue-Cross Blue-Shield of Michigan |
| OIZ | California | Anthem Blue-Cross |
| OJA | - | Unallocated/Not Assigned |
| OJB | - | Unallocated/Not Assigned |
| OJC | - | Unallocated/Not Assigned |
| OJD | - | Unallocated/Not Assigned |
| OJE | Michigan | Blue-Cross Blue-Shield of Michigan |
| OJF | Michigan | Blue-Cross Blue-Shield of Michigan |
| OJG | - | Unallocated/Not Assigned |
| OJH | - | Unallocated/Not Assigned |
| OJI | Michigan | Blue-Cross Blue-Shield of Michigan |
| OJJ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OJK | Michigan | Blue-Cross Blue-Shield of Michigan |
| OJL | Michigan | Blue-Cross Blue-Shield of Michigan |
| OJM | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| OJN | Michigan | Blue-Cross Blue-Shield of Michigan |
| OJO | Michigan | Blue-Cross Blue-Shield of Michigan |
| OJP | Rhode Island | Blue-Cross Blue-Shield of Rhode Island |
| OJQ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OJR | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OJS | - | Unallocated/Not Assigned |
| OJT | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OJU | - | Unallocated/Not Assigned |
| OJV | Michigan | Blue-Cross Blue-Shield of Michigan |
| OJW | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| OJX | Michigan | Blue-Cross Blue-Shield of Michigan |
| OJY | Michigan | Blue-Cross Blue-Shield of Michigan |
| OJZ | - | Unallocated/Not Assigned |
| OKA | Minnesota | Blue-Cross Blue-Shield of Minnesota |
| OKB | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OKC | Oklahoma | Blue-Cross Blue-Shield of Oklahoma |
| OKD | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| OKE | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OKF | Michigan | Blue-Cross Blue-Shield of Michigan |
| OKG | Michigan | Blue-Cross Blue-Shield of Michigan |
| OKH | California | Anthem Blue-Cross |
| OKI | Michigan | Blue-Cross Blue-Shield of Michigan |
| OKJ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OKK | Michigan | Blue-Cross Blue-Shield of Michigan |
| OKL | Arkansas | Arkansas Blue-Cross Blue-Shield |
| OKM | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| OKN | Michigan | Blue-Cross Blue-Shield of Michigan |
| OKO | Michigan | Blue-Cross Blue-Shield of Michigan |
| OKP | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| OKQ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OKR | Colorado | Anthem Blue-Cross Blue-Shield of Colorado |
| OKS | New York (Western) | Blue-Cross Blue-Shield of Western New York |
| OKT | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| OKU | - | Unallocated/Not Assigned |
| OKV | Michigan | Blue-Cross Blue-Shield of Michigan |
| OKW | California | Anthem Blue-Cross |
| OKX | Michigan | Blue-Cross Blue-Shield of Michigan |
| OKY | Michigan | Blue-Cross Blue-Shield of Michigan |
| OKZ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OLA | Kansas City | Blue-Cross Blue-Shield of Kansas City |
| OLB | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OLC | - | Unallocated/Not Assigned |
| OLD | California | Blue-Shield of California |
| OLE | - | Unallocated/Not Assigned |
| OLF | - | Unallocated/Not Assigned |
| OLG | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| OLH | Arizona | Blue-Cross Blue-Shield of Arizona |
| OLI | Michigan | Blue-Cross Blue-Shield of Michigan |
| OLJ | - | Unallocated/Not Assigned |
| OLK | - | Unallocated/Not Assigned |
| OLL | - | Unallocated/Not Assigned |
| OLM | Arkansas | Arkansas Blue-Cross Blue-Shield |
| OLN | Alabama | Blue-Cross Blue-Shield of Alabama |
| OLO | - | Unallocated/Not Assigned |
| OLP | - | Unallocated/Not Assigned |
| OLQ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OLR | - | Unallocated/Not Assigned |
| OLS | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OLT | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OLU | Colorado | Anthem Blue-Cross Blue-Shield of Colorado |
| OLV | Michigan | Blue-Cross Blue-Shield of Michigan |
| OLW | New York (Western) | Blue-Cross Blue-Shield of Western New York |
| OLX | Michigan | Blue-Cross Blue-Shield of Michigan |
| OLY | Michigan | Blue-Cross Blue-Shield of Michigan |
| OLZ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OMA | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| OMB | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| OMC | - | Unallocated/Not Assigned |
| OMD | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| OME | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OMF | - | Unallocated/Not Assigned |
| OMG | Michigan | Blue-Cross Blue-Shield of Michigan |
| OMH | California | Blue-Shield of California |
| OMI | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| OMJ | - | Unallocated/Not Assigned |
| OMK | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| OML | Florida | Florida-Blue |
| OMM | - | Unallocated/Not Assigned |
| OMN | - | Unallocated/Not Assigned |
| OMO | - | Unallocated/Not Assigned |
| OMP | Michigan | Blue-Cross Blue-Shield of Michigan |
| OMQ | Massachusetts | Blue-Cross Blue-Shield of Massachusetts |
| OMR | Rhode Island | Blue-Cross Blue-Shield of Rhode Island |
| OMS | Massachusetts | Blue-Cross Blue-Shield of Massachusetts |
| OMT | Michigan | Blue-Cross Blue-Shield of Michigan |
| OMU | - | Unallocated/Not Assigned |
| OMV | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OMW | - | Unallocated/Not Assigned |
| OMX | Colorado | Anthem Blue-Cross Blue-Shield of Colorado |
| OMY | - | Unallocated/Not Assigned |
| OMZ | California | Blue-Shield of California |
| ONA | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| ONB | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| ONC | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| OND | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| ONE | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| ONF | - | Unallocated/Not Assigned |
| ONG | Massachusetts | Blue-Cross Blue-Shield of Massachusetts |
| ONH | Minnesota | Blue-Cross Blue-Shield of Minnesota |
| ONI | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| ONJ | - | Unallocated/Not Assigned |
| ONK | - | Unallocated/Not Assigned |
| ONL | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| ONM | - | Unallocated/Not Assigned |
| ONN | - | Unallocated/Not Assigned |
| ONO | California | Blue-Shield of California |
| ONP | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| ONQ | Alabama | Blue-Cross Blue-Shield of Alabama |
| ONR | - | Unallocated/Not Assigned |
| ONS | Alabama | Blue-Cross Blue-Shield of Alabama |
| ONT | Massachusetts | Blue-Cross Blue-Shield of Massachusetts |
| ONU | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| ONV | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| ONW | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| ONX | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| ONY | Minnesota | Blue-Cross Blue-Shield of Minnesota |
| ONZ | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| OOA | California | Blue-Shield of California |
| OOB | California | Blue-Shield of California |
| OOC | Massachusetts | Blue-Cross Blue-Shield of Massachusetts |
| OOD | Michigan | Blue-Cross Blue-Shield of Michigan |
| OOE | Michigan | Blue-Cross Blue-Shield of Michigan |
| OOF | Michigan | Blue-Cross Blue-Shield of Michigan |
| OOG | California | Blue-Shield of California |
| OOH | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| OOI | Michigan | Blue-Cross Blue-Shield of Michigan |
| OOJ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OOK | Michigan | Blue-Cross Blue-Shield of Michigan |
| OOL | Rhode Island | Blue-Cross Blue-Shield of Rhode Island |
| OOM | California | Anthem Blue-Cross |
| OON | Michigan | Blue-Cross Blue-Shield of Michigan |
| OOO | Michigan | Blue-Cross Blue-Shield of Michigan |
| OOP | California | Blue-Shield of California |
| OOQ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OOR | North Carolina | Blue-Cross Blue-Shield of North Carolina |
| OOS | California | Blue-Shield of California |
| OOT | California | Blue-Shield of California |
| OOU | Michigan | Blue-Cross Blue-Shield of Michigan |
| OOV | Michigan | Blue-Cross Blue-Shield of Michigan |
| OOW | Michigan | Blue-Cross Blue-Shield of Michigan |
| OOX | Michigan | Blue-Cross Blue-Shield of Michigan |
| OOY | - | Unallocated/Not Assigned |
| OOZ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OPA | Louisiana | Blue-Cross Blue-Shield of Louisiana |
| OPB | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| OPC | - | Unallocated/Not Assigned |
| OPD | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| OPE | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| OPF | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| OPG | California | Anthem Blue-Cross |
| OPH | - | Unallocated/Not Assigned |
| OPI | North Carolina | Blue-Cross of North Carolina |
| OPJ | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| OPK | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| OPL | - | Unallocated/Not Assigned |
| OPM | - | Unallocated/Not Assigned |
| OPN | - | Unallocated/Not Assigned |
| OPO | - | Unallocated/Not Assigned |
| OPP | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OPQ | - | Unallocated/Not Assigned |
| OPR | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OPS | Massachusetts | Blue-Cross Blue-Shield of Massachusetts |
| OPT | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OPU | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| OPV | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| OPW | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| OPX | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| OPY | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| OPZ | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| OQA | - | Unallocated/Not Assigned |
| OQB | California | Anthem Blue-Cross |
| OQC | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| OQD | Michigan | Blue-Cross Blue-Shield of Michigan |
| OQE | Michigan | Blue-Cross Blue-Shield of Michigan |
| OQF | Michigan | Blue-Cross Blue-Shield of Michigan |
| OQG | Michigan | Blue-Cross Blue-Shield of Michigan |
| OQH | Michigan | Blue-Cross Blue-Shield of Michigan |
| OQI | Michigan | Blue-Cross Blue-Shield of Michigan |
| OQJ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OQK | Michigan | Blue-Cross Blue-Shield of Michigan |
| OQL | Michigan | Blue-Cross Blue-Shield of Michigan |
| OQM | Michigan | Blue-Cross Blue-Shield of Michigan |
| OQN | Michigan | Blue-Cross Blue-Shield of Michigan |
| OQO | Michigan | Blue-Cross Blue-Shield of Michigan |
| OQP | California | Anthem Blue-Cross |
| OQQ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OQR | Michigan | Blue-Cross Blue-Shield of Michigan |
| OQS | California | Anthem Blue-Cross |
| OQT | Michigan | Blue-Cross Blue-Shield of Michigan |
| OQU | Michigan | Blue-Cross Blue-Shield of Michigan |
| OQV | Michigan | Blue-Cross Blue-Shield of Michigan |
| OQW | Michigan | Blue-Cross Blue-Shield of Michigan |
| OQX | - | Unallocated/Not Assigned |
| OQY | - | Unallocated/Not Assigned |
| OQZ | - | Unallocated/Not Assigned |
| ORA | - | Unallocated/Not Assigned |
| ORB | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| ORC | Kentucky | Anthem Blue-Cross Blue-Shield of Kentucky |
| ORD | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| ORE | Tennessee | Blue-Cross Blue-Shield of Tennessee |
| ORF | Michigan | Blue-Cross Blue-Shield of Michigan |
| ORG | Tennessee | Blue-Cross Blue-Shield of Tennessee |
| ORH | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| ORI | South Carolina | Blue-Cross Blue-Shield of South Carolina |
| ORJ | Michigan | Blue-Cross Blue-Shield of Michigan |
| ORK | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| ORL | California | Anthem Blue-Cross |
| ORM | New York (Northeastern) | Blue-Shield of Northeastern New York |
| ORN | New Jersey | Horizon Blue-Cross Blue-Shield of New Jersey |
| ORO | Michigan | Blue-Cross Blue-Shield of Michigan |
| ORP | - | Unallocated/Not Assigned |
| ORQ | Michigan | Blue-Cross Blue-Shield of Michigan |
| ORR | - | Unallocated/Not Assigned |
| ORS | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| ORT | Pennsylvania | Capital Blue-Cross of Pennsylvania |
| ORU | Tennessee | Blue-Cross Blue-Shield of Tennessee |
| ORV | Michigan | Blue-Cross Blue-Shield of Michigan |
| ORW | - | Unallocated/Not Assigned |
| ORX | Idaho | Blue-Cross of Idaho |
| ORY | California | Blue-Shield of California |
| ORZ | New Jersey | Horizon Blue-Cross Blue-Shield of New Jersey |
| OSA | - | Unallocated/Not Assigned |
| OSB | Alabama | Blue-Cross Blue-Shield of Alabama |
| OSC | - | Unallocated/Not Assigned |
| OSD | - | Unallocated/Not Assigned |
| OSE | Arizona | Blue-Cross Blue-Shield of Arizona |
| OSF | - | Unallocated/Not Assigned |
| OSG | - | Unallocated/Not Assigned |
| OSH | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OSI | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| OSJ | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| OSK | - | Unallocated/Not Assigned |
| OSL | Nebraska | Blue-Cross Blue-Shield of Nebraska |
| OSM | Illinois | Blue-Cross Blue-Shield of Illinois |
| OSN | - | Unallocated/Not Assigned |
| OSO | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| OSP | - | Unallocated/Not Assigned |
| OSQ | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| OSR | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| OSS | California | Blue-Shield of California |
| OST | Delaware | Highmark Blue-Cross Blue-Shield of Delaware |
| OSU | - | Unallocated/Not Assigned |
| OSV | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| OSW | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| OSX | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OSY | Kansas City | Blue-Cross Blue-Shield of Kansas City |
| OSZ | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| OTA | Florida | Florida-Blue |
| OTB | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| OTC | Nebraska | Blue-Cross Blue-Shield of Nebraska |
| OTD | California | Anthem Blue-Cross |
| OTE | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| OTF | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| OTG | Michigan | Blue-Cross Blue-Shield of Michigan |
| OTH | Tennessee | Blue-Cross Blue-Shield of Tennessee |
| OTI | North Dakota | Blue-Cross Blue-Shield of North Dakota |
| OTJ | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OTK | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OTL | Alabama | Blue-Cross Blue-Shield of Alabama |
| OTM | California | Blue-Shield of California |
| OTN | North Dakota | Blue-Cross Blue-Shield of North Dakota |
| OTO BCBS Prefix | - | Unallocated/Not Assigned |
| OTP | California | Blue-Shield of California |
| OTQ | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| OTR | - | Unallocated/Not Assigned |
| OTS | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| OTT | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OTU | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OTV | - | Unallocated/Not Assigned |
| OTW | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| OTX | California | Blue-Shield of California |
| OTY | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| OTZ | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| OUA | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| OUB | Rhode Island | Blue-Cross Blue-Shield of Rhode Island |
| OUC | South Carolina | Blue-Cross Blue-Shield of South Carolina |
| OUD | Michigan | Blue-Cross Blue-Shield of Michigan |
| OUE | Rhode Island | Blue-Cross Blue-Shield of Rhode Island |
| OUF | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| OUG | - | Unallocated/Not Assigned |
| OUH | New York | Empire Blue-Cross Blue-Shield of New York |
| OUI | New Jersey | Horizon Blue-Cross Blue-Shield of New Jersey |
| OUJ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OUK | Michigan | Blue-Cross Blue-Shield of Michigan |
| OUL | Michigan | Blue-Cross Blue-Shield of Michigan |
| OUM | Michigan | Blue-Cross Blue-Shield of Michigan |
| OUN | Michigan | Blue-Cross Blue-Shield of Michigan |
| OUO | Michigan | Blue-Cross Blue-Shield of Michigan |
| OUP | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OUQ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OUR | New Jersey | Horizon Blue-Cross Blue-Shield of New Jersey |
| OUS | - | Unallocated/Not Assigned |
| OUT | New Jersey | Horizon Blue-Cross Blue-Shield of New Jersey |
| OUU | Michigan | Blue-Cross Blue-Shield of Michigan |
| OUV | Michigan | Blue-Cross Blue-Shield of Michigan |
| OUW | West Virginia | Highmark Blue-Cross Blue-Shield of West Virginia |
| OUX | Michigan | Blue-Cross Blue-Shield of Michigan |
| OUY | Michigan | Blue-Cross Blue-Shield of Michigan |
| OUZ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OVA | - | Unallocated/Not Assigned |
| OVB | - | Unallocated/Not Assigned |
| OVC | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| OVD | Michigan | Blue-Cross Blue-Shield of Michigan |
| OVE | - | Unallocated/Not Assigned |
| OVF | - | Unallocated/Not Assigned |
| OVG | Michigan | Blue-Cross Blue-Shield of Michigan |
| OVH | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| OVI | Michigan | Blue-Cross Blue-Shield of Michigan |
| OVJ | - | Unallocated/Not Assigned |
| OVK | - | Unallocated/Not Assigned |
| OVL | New York (Western) | Blue-Cross Blue-Shield of Western New York |
| OVM | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OVN | Michigan | Blue-Cross Blue-Shield of Michigan |
| OVO | Michigan | Blue-Cross Blue-Shield of Michigan |
| OVP | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| OVQ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OVR | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OVS | - | Unallocated/Not Assigned |
| OVT | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| OVU | Michigan | Blue-Cross Blue-Shield of Michigan |
| OVV | Michigan | Blue-Cross Blue-Shield of Michigan |
| OVW | West Virginia | Highmark Blue-Cross Blue-Shield of West Virginia |
| OVX | Michigan | Blue-Cross Blue-Shield of Michigan |
| OVY | Michigan | Blue-Cross Blue-Shield of Michigan |
| OVZ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OWA | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OWB | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OWC | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| OWD | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| OWE | Florida | Florida-Blue |
| OWF | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OWG | New York (Western) | Blue-Cross Blue-Shield of Western New York |
| OWH | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| OWI | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| OWJ | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| OWK | Michigan | Blue-Cross Blue-Shield of Michigan |
| OWL | California | Blue-Shield of California |
| OWM | - | Unallocated/Not Assigned |
| OWN | - | Unallocated/Not Assigned |
| OWO | Michigan | Blue-Cross Blue-Shield of Michigan |
| OWP | - | Unallocated/Not Assigned |
| OWQ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OWR | Michigan | Blue-Cross Blue-Shield of Michigan |
| OWS | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| OWT | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| OWU | Michigan | Blue-Cross Blue-Shield of Michigan |
| OWV | - | Unallocated/Not Assigned |
| OWW | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| OWX | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| OWY | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| OWZ | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OXA | New York (Western) | Blue-Cross Blue-Shield of Western New York |
| OXB | - | Unallocated/Not Assigned |
| OXC | - | Unallocated/Not Assigned |
| OXD | California | Anthem Blue-Cross |
| OXE | Michigan | Blue-Cross Blue-Shield of Michigan |
| OXF | - | Unallocated/Not Assigned |
| OXG | Michigan | Blue-Cross Blue-Shield of Michigan |
| OXH | Michigan | Blue-Cross Blue-Shield of Michigan |
| OXI | Michigan | Blue-Cross Blue-Shield of Michigan |
| OXJ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OXK | Michigan | Blue-Cross Blue-Shield of Michigan |
| OXL | Michigan | Blue-Cross Blue-Shield of Michigan |
| OXM | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| OXN | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| OXO | New York (Western) | Blue-Cross Blue-Shield of Western New York |
| OXP | California | Anthem Blue-Cross |
| OXQ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OXR | Michigan | Blue-Cross Blue-Shield of Michigan |
| OXS | - | Unallocated/Not Assigned |
| OXT | Michigan | Blue-Cross Blue-Shield of Michigan |
| OXU | Michigan | Blue-Cross Blue-Shield of Michigan |
| OXV | Michigan | Blue-Cross Blue-Shield of Michigan |
| OXW | Michigan | Blue-Cross Blue-Shield of Michigan |
| OXX | Michigan | Blue-Cross Blue-Shield of Michigan |
| OXY | Michigan | Blue-Cross Blue-Shield of Michigan |
| OXZ | - | Unallocated/Not Assigned |
| OYA | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| OYB | California | Anthem Blue-Cross |
| OYC | New Jersey | Horizon Blue-Cross Blue-Shield of New Jersey |
| OYD | Idaho | Blue-Cross of Idaho |
| OYE | - | Unallocated/Not Assigned |
| OYF | Michigan | Blue-Cross Blue-Shield of Michigan |
| OYG | Michigan | Blue-Cross Blue-Shield of Michigan |
| OYH | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| OYI | Michigan | Blue-Cross Blue-Shield of Michigan |
| OYJ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OYK | Michigan | Blue-Cross Blue-Shield of Michigan |
| OYL | California | Blue-Shield of California |
| OYM | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| OYN | Michigan | Blue-Cross Blue-Shield of Michigan |
| OYO | Michigan | Blue-Cross Blue-Shield of Michigan |
| OYP | - | Unallocated/Not Assigned |
| OYQ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OYR | Michigan | Blue-Cross Blue-Shield of Michigan |
| OYS | California | Blue-Shield of California |
| OYT | Michigan | Blue-Cross Blue-Shield of Michigan |
| OYU | Michigan | Blue-Cross Blue-Shield of Michigan |
| OYV | - | Unallocated/Not Assigned |
| OYW | Michigan | Blue-Cross Blue-Shield of Michigan |
| OYX | Michigan | Blue-Cross Blue-Shield of Michigan |
| OYY | Michigan | Blue-Cross Blue-Shield of Michigan |
| OYZ | - | Unallocated/Not Assigned |
| OZA | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| OZB | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| OZC | New Jersey | Horizon Blue-Cross Blue-Shield of New Jersey |
| OZD | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| OZE | Michigan | Blue-Cross Blue-Shield of Michigan |
| OZF | Michigan | Blue-Cross Blue-Shield of Michigan |
| OZG | California | Blue-Shield of California |
| OZH | - | Unallocated/Not Assigned |
| OZI | Michigan | Blue-Cross Blue-Shield of Michigan |
| OZJ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OZK | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| OZL | Michigan | Blue-Cross Blue-Shield of Michigan |
| OZM | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| OZN | Michigan | Blue-Cross Blue-Shield of Michigan |
| OZO | - | Unallocated/Not Assigned |
| OZP | California | Anthem Blue-Cross |
| OZQ | Michigan | Blue-Cross Blue-Shield of Michigan |
| OZR | Michigan | Blue-Cross Blue-Shield of Michigan |
| OZS | New York (Western) | Blue-Cross Blue-Shield of Western New York |
| OZT | Michigan | Blue-Cross Blue-Shield of Michigan |
| OZU | Michigan | Blue-Cross Blue-Shield of Michigan |
| OZV | Michigan | Blue-Cross Blue-Shield of Michigan |
| OZW | - | Unallocated/Not Assigned |
| OZX | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| OZY | Michigan | Blue-Cross Blue-Shield of Michigan |
| OZZ | Michigan | Blue-Cross Blue-Shield of Michigan |