| UAA | BCBS of Michigan |
| UAB | BCBS of Kansas City |
| UAC | BCBS of Michigan |
| UAD | No Prefix Assigned |
| UAE | Blue-Shield of California |
| UAF | Blue-Shield of California |
| UAG | BCBS of Texas |
| UAH | BCBS of Alabama |
| UAI | No Prefix Assigned |
| UAJ | No Prefix Assigned |
| UAK | Anthem BCBS of Connecticut |
| UAL | BCBS of Illinois |
| UAM | Highmark BCBS of Pennsylvania |
| UAN | Horizon BCBS of New Jersey |
| UAO | BCBS of Michigan |
| UAP | No Prefix Assigned |
| UAQ | Blue-Shield of California |
| UAR | BCBS of Texas |
| UAS | Anthem Blue-Cross |
| UAT | Anthem Blue-Cross |
| UAU | BCBS of Michigan |
| UAV | Anthem Blue-Cross |
| UAW | BCBS of Michigan |
| UAX | Empire BCBS of New York |
| UAY | BCBS of Michigan |
| UAZ | Carefirst BCBS |
| UBA | Anthem BCBS of Virginia |
| UBB | Anthem BCBS of Missouri |
| UBC | Anthem BCBS of Ohio |
| UBD | Anthem BCBS of Ohio |
| UBE | No Prefix Assigned |
| UBF | Independence Blue Cross of Philadelphia/Southeastern Pennsylvania |
| UBG | BCBS of Michigan |
| UBH | BCBS of Minnesota |
| UBI | No Prefix Assigned |
| UBJ | No Prefix Assigned |
| UBK | No Prefix Assigned |
| UBL | Independence Blue Cross of Philadelphia/Southeastern Pennsylvania |
| UBM | Anthem BCBS of Virginia |
| UBN | No Prefix Assigned |
| UBO | Blue-Shield of California |
| UBP | Wellmark BCBS |
| UBQ | No Prefix Assigned |
| UBR | Anthem BCBS of Kentucky |
| UBS | Blue-Shield of California |
| UBT | No Prefix Assigned |
| UBU | Anthem BCBS of Virginia |
| UBV | Wellmark BCBS |
| UBW | No Prefix Assigned |
| UBX | Wellmark BCBS |
| UBY | No Prefix Assigned |
| UBZ | Anthem BCBS of Indiana |
| UCA | Anthem BCBS of Ohio |
| UCB | Premera BCBS of Alaska |
| UCC | BCBS of Michigan |
| UCD | No Prefix Assigned |
| UCE | BCBS of Texas |
| UCF | No Prefix Assigned |
| UCG | BCBS of Massachusetts |
| UCH | BCBS of Kansas City |
| UCI | BCBS of Michigan |
| UCJ | Horizon BCBS of New Jersey |
| UCK | BCBS of Michigan |
| UCL | Anthem BCBS of Colorado |
| UCM | No Prefix Assigned |
| UCN | BCBS of Alabama |
| UCO | Carefirst BCBS |
| UCP | Wellmark BCBS |
| UCQ | Anthem BCBS of Ohio |
| UCR | Anthem BCBS of Missouri |
| UCS | Regence BCBS |
| UCT | No Prefix Assigned |
| UCU | No Prefix Assigned |
| UCV | No Prefix Assigned |
| UCW | BCBS of Tennessee |
| UCX | Anthem BCBS of Ohio |
| UCY | No Prefix Assigned |
| UCZ | No Prefix Assigned |
| UDA | Premera BCBS of Alaska |
| UDB | Wellmark BCBS |
| UDC | BCBS of Michigan |
| UDD | BCBS of Michigan |
| UDE | Anthem BCBS of Indiana |
| UDF | No Prefix Assigned |
| UDG | No Prefix Assigned |
| UDH | BCBS of Illinois |
| UDI | Anthem BCBS of Nevada |
| UDJ | No Prefix Assigned |
| UDK | No Prefix Assigned |
| UDL | BCBS of Illinois |
| UDM | Highmark BCBS of Pennsylvania |
| UDN | Anthem BCBS of Wisconsin |
| UDO | Anthem BCBS of Ohio |
| UDP | Carefirst BCBS |
| UDQ | BCBS of Michigan |
| UDR | Anthem BCBS of Georgia |
| UDS | Independence Blue Cross of Philadelphia/Southeastern Pennsylvania |
| UDT | Anthem BCBS of Indiana |
| UDU | No Prefix Assigned |
| UDV | Premera BCBS of Alaska |
| UDW | Regence BCBS |
| UDX | BCBS of Michigan |
| UDY | Anthem BCBS of Indiana |
| UDZ | No Prefix Assigned |
| UEA | BCBS of Kansas City |
| UEB | BCBS of Massachusetts |
| UEC | Blue-Shield of California |
| UED | Wellmark BCBS |
| UEE | BCBS of Tennessee |
| UEF | Blue-Shield of California |
| UEG | Empire BCBS of New York |
| UEH | Anthem BCBS of Missouri |
| UEI | Anthem BCBS of Indiana |
| UEJ | BCBS of Illinois |
| UEK | Wellmark BCBS |
| UEL | BCBS of Massachusetts |
| UEM | BCBS of Massachusetts |
| UEN | BCBS of Massachusetts |
| UEO | Regence BCBS |
| UEP | No Prefix Assigned |
| UEQ | Anthem BCBS of Missouri |
| UER | Carefirst BCBS |
| UES | Empire BCBS of New York |
| UET | Anthem BCBS of Virginia |
| UEU | No Prefix Assigned |
| UEV | No Prefix Assigned |
| UEW | BCBS of Massachusetts |
| UEX | BCBS of Texas |
| UEY | No Prefix Assigned |
| UEZ | BCBS of Illinois |
| UFA | Anthem BCBS of Nevada |
| UFB | BCBS of Michigan |
| UFC | BCBS of Illinois |
| UFD | Horizon BCBS of New Jersey |
| UFE | No Prefix Assigned |
| UFF | Anthem BCBS of Ohio |
| UFG | BCBS of Michigan |
| UFH | BCBS of Michigan |
| UFI | Anthem BCBS of Ohio |
| UFJ | BCBS of Michigan |
| UFK | BCBS of Michigan |
| UFL | BCBS of Michigan |
| UFM | No Prefix Assigned |
| UFN | Independence Blue Cross of Philadelphia/Southeastern Pennsylvania |
| UFO | No Prefix Assigned |
| UFP | Independence Blue Cross of Philadelphia/Southeastern Pennsylvania |
| UFQ | BCBS of Michigan |
| UFR | BCBS of Western New York |
| UFS | Florida-Blue |
| UFT | Independence Blue Cross of Philadelphia/Southeastern Pennsylvania |
| UFU | Excellus BCBS of New York |
| UFV | BCBS of Michigan |
| UFW | BCBS of Illinois |
| UFX | BCBS of Michigan |
| UFY | Wellmark BCBS |
| UFZ | Highmark BCBS of Pennsylvania |
| UGA | Florida-Blue |
| UGB | Anthem Blue-Cross |
| UGC | Horizon BCBS of New Jersey |
| UGD | BCBS of Michigan |
| UGE | No Prefix Assigned |
| UGF | BCBS of Michigan |
| UGG | BCBS of Michigan |
| UGH | BCBS of Michigan |
| UGI | No Prefix Assigned |
| UGJ | Anthem Blue-Cross |
| UGK | Anthem Blue-Cross |
| UGL | Highmark BCBS of Pennsylvania |
| UGM | No Prefix Assigned |
| UGN | BCBS of Illinois |
| UGO | Anthem BCBS of Indiana |
| UGP | BCBS of Michigan |
| UGQ | Blue-Cross of Idaho |
| UGR | Anthem BCBS of New Hampshire |
| UGS | Anthem BCBS of New Hampshire |
| UGT | BCBS of Alabama |
| UGU | BCBS of Tennessee |
| UGV | BCBS of Minnesota |
| UGW | Anthem Blue-Cross |
| UGX | BCBS of Illinois |
| UGY | Horizon BCBS of New Jersey |
| UGZ | BCBS of Michigan |
| UHA | No Prefix Assigned |
| UHB | No Prefix Assigned |
| UHC | BCBS of Michigan |
| UHD | Anthem BCBS of Ohio |
| UHE | BCBS of Arizona |
| UHF | Independence Blue Cross of Philadelphia/Southeastern Pennsylvania |
| UHG | No Prefix Assigned |
| UHH | Wellmark BCBS |
| UHI | Anthem BCBS of Ohio |
| UHJ | BCBS of Michigan |
| UHK | Anthem BCBS of Ohio |
| UHL | BCBS of Arizona |
| UHM | BCBS of Massachusetts |
| UHN | Carefirst BCBS |
| UHO | BCBS of Illinois |
| UHP | BCBS of Alabama |
| UHQ | Anthem BCBS of Ohio |
| UHR | Highmark BCBS of Pennsylvania |
| UHS | BCBS of Illinois |
| UHT | Anthem BCBS of Ohio |
| UHU | Anthem BCBS of Indiana |
| UHV | Anthem BCBS of Indiana |
| UHW | BCBS of Illinois |
| UHX | BCBS of Minnesota |
| UHY | Blue-Shield of Northeastern New York |
| UHZ | Blue-Shield of Northeastern New York |
| UIA | No Prefix Assigned |
| UIB | No Prefix Assigned |
| UIC | BCBS of Michigan |
| UID | Blue-Cross of Idaho |
| UIE | BCBS of Michigan |
| UIF | Florida-Blue |
| UIG | Excellus BCBS of New York |
| UIH | Carefirst BCBS |
| UII | BCBS of Michigan |
| UIJ | Anthem BCBS of Georgia |
| UIK | Anthem BCBS of Georgia |
| UIL | BCBS of Michigan |
| UIM | Premera BCBS of Alaska |
| UIN | BCBS of Michigan |
| UIO | BCBS of Michigan |
| UIP | Anthem Blue-Cross |
| UIQ | Carefirst BCBS |
| UIR | BCBS of Michigan |
| UIS | No Prefix Assigned |
| UIT | Anthem BCBS of Colorado |
| UIU | Carefirst BCBS |
| UIV | Premera BCBS of Alaska |
| UIW | BCBS of Michigan |
| UIX | Horizon BCBS of New Jersey |
| UIY | Carefirst BCBS |
| UIZ | No Prefix Assigned |
| UJA | Anthem BCBS of Connecticut |
| UJB | Anthem BCBS of Missouri |
| UJC | BCBS of Illinois |
| UJD | Premera BCBS of Alaska |
| UJE | No Prefix Assigned |
| UJF | BCBS of Alabama |
| UJG | BCBS of Oklahoma |
| UJH | BCBS of Illinois |
| UJI | Anthem BCBS of Wisconsin |
| UJJ | Anthem BCBS of Wisconsin |
| UJK | No Prefix Assigned |
| UJL | No Prefix Assigned |
| UJM | Anthem BCBS of Wisconsin |
| UJN | Anthem BCBS of New Hampshire |
| UJO | Anthem BCBS of Ohio |
| UJP | BCBS of Illinois |
| UJQ | BCBS of Texas |
| UJR | Regence BCBS |
| UJS | Highmark BCBS of Pennsylvania |
| UJT | Regence BCBS |
| UJU | No Prefix Assigned |
| UJV | No Prefix Assigned |
| UJW | No Prefix Assigned |
| UJX | Independence Blue Cross of Philadelphia/Southeastern Pennsylvania |
| UJY | Anthem BCBS of Wisconsin |
| UJZ | Anthem BCBS of Wisconsin |
| UKA | No Prefix Assigned |
| UKB | BCBS of Massachusetts |
| UKC | BCBS of Oklahoma |
| UKD | BCBS of Oklahoma |
| UKE | Anthem Blue-Cross |
| UKF | No Prefix Assigned |
| UKG | No Prefix Assigned |
| UKH | Empire BCBS of New York |
| UKI | Anthem BCBS of Georgia |
| UKJ | Empire BCBS of New York |
| UKK | No Prefix Assigned |
| UKL | BCBS of Texas |
| UKM | No Prefix Assigned |
| UKN | Blue-Cross of Idaho |
| UKO | Wellmark BCBS |
| UKP | No Prefix Assigned |
| UKQ | Premera Blue-Cross of Alaska |
| UKR | No Prefix Assigned |
| UKS | Anthem BCBS of Missouri |
| UKT | Anthem Blue-Cross |
| UKU | BCBS of Tennessee |
| UKV | No Prefix Assigned |
| UKW | BCBS of Massachusetts |
| UKX | BCBS of Nebraska |
| UKY | Anthem BCBS of Ohio |
| UKZ | No Prefix Assigned |
| ULA | Anthem BCBS of Colorado |
| ULB | Anthem BCBS of Ohio |
| ULC | Anthem BCBS of Ohio |
| ULD | Premera BCBS of Alaska |
| ULE | BCBS of Illinois |
| ULF | BCBS of Illinois |
| ULG | No Prefix Assigned |
| ULH | Anthem BCBS of Kentucky |
| ULI | Independence Blue Cross of Philadelphia/Southeastern Pennsylvania |
| ULJ | BCBS of Michigan |
| ULK | BCBS of Western New York |
| ULL | Carefirst BCBS |
| ULM | Carefirst BCBS |
| ULN | BCBS of Kansas City |
| ULO | BCBS of Michigan |
| ULP | BCBS of Alabama |
| ULQ | Anthem BCBS of Ohio |
| ULR | Anthem BCBS of Georgia |
| ULS | Anthem BCBS of Ohio |
| ULT | BCBS of Illinois |
| ULU | Anthem BCBS of Ohio |
| ULV | Carefirst BCBS |
| ULW | Wellmark BCBS |
| ULX | No Prefix Assigned |
| ULY | BCBS of Illinois |
| ULZ | BCBS of Tennessee |
| UMA | BCBS of Massachusetts |
| UMB | Blue-Cross of Idaho |
| UMC | BCBS of Minnesota |
| UMD | Highmark BCBS of Pennsylvania |
| UME | Florida-Blue |
| UMF | BCBS of Illinois |
| UMG | Anthem Blue-Cross |
| UMH | Anthem BCBS of Ohio |
| UMI | BCBS of Massachusetts |
| UMJ | Carefirst BCBS |
| UMK | BCBS of Michigan |
| UML | BCBS of Michigan |
| UMM | Anthem BCBS of Virginia |
| UMN | BCBS of Michigan |
| UMO | Anthem Blue-Cross |
| UMP | No Prefix Assigned |
| UMQ | Anthem BCBS of Nevada |
| UMR | Premera BCBS of Alaska |
| UMS | BCBS of Michigan |
| UMT | BCBS of Michigan |
| UMU | BCBS of Michigan |
| UMV | BCBS of Michigan |
| UMW | BCBS of Michigan |
| UMX | Premera BCBS of Alaska |
| UMY | Carefirst BCBS |
| UMZ | Premera BCBS of Alaska |
| UNA | Anthem BCBS of Wisconsin |
| UNB | BCBS of Nebraska |
| UNC | BCBS of Michigan |
| UND | No Prefix Assigned |
| UNE | No Prefix Assigned |
| UNF | BCBS of Arizona |
| UNG | BCBS of North Carolina |
| UNH | No Prefix Assigned |
| UNI | Anthem BCBS of Wisconsin |
| UNJ | Anthem BCBS of Indiana |
| UNK | BCBS of Tennessee |
| UNL | Anthem Blue-Cross |
| UNM | Carefirst BCBS |
| UNN | Premera BCBS of Alaska |
| UNO | No Prefix Assigned |
| UNP | BCBS of Michigan |
| UNQ | Carefirst BCBS |
| UNR | Anthem Blue-Cross |
| UNS | Blue-Cross of Vermont |
| UNT | Blue-Cross of Vermont |
| UNU | Empire BCBS of New York |
| UNV | Anthem BCBS of Ohio |
| UNW | Florida-Blue |
| UNX | Anthem BCBS of Connecticut |
| UNY | No Prefix Assigned |
| UNZ | Empire BCBS of New York |
| UOA | No Prefix Assigned |
| UOB | Wellmark BCBS |
| UOC | BCBS of Illinois |
| UOD | No Prefix Assigned |
| UOE | BCBS of Illinois |
| UOF | BCBS of Michigan |
| UOG | Horizon BCBS of New Jersey |
| UOH | Premera BCBS of Alaska |
| UOI | Blue-Cross of Idaho |
| UOJ | No Prefix Assigned |
| UOK | No Prefix Assigned |
| UOL | No Prefix Assigned |
| UOM | BCBS of Michigan |
| UON | Wellmark BCBS |
| UOO | BCBS of Michigan |
| UOP | Anthem BCBS of Ohio |
| UOQ | Horizon BCBS of New Jersey |
| UOR | No Prefix Assigned |
| UOS | No Prefix Assigned |
| UOT | Blue-Shield of California |
| UOU | Regence BCBS |
| UOV | No Prefix Assigned |
| UOW | No Prefix Assigned |
| UOX | Anthem BCBS of Ohio |
| UOY | BCBS of Michigan |
| UOZ | Highmark BCBS of Pennsylvania |
| UPA | BCBS of Illinois |
| UPB | Independence Blue Cross of Philadelphia/Southeastern Pennsylvania |
| UPC | Carefirst BCBS |
| UPD | Anthem BCBS of Wisconsin |
| UPE | No Prefix Assigned |
| UPF | Wellmark BCBS |
| UPG | Anthem BCBS of Ohio |
| UPH | BCBS of Illinois |
| UPI | BCBS of Alabama |
| UPJ | Premera BCBS of Alaska |
| UPK | No Prefix Assigned |
| UPL | No Prefix Assigned |
| UPM | BCBS of Rhode Island |
| UPN | No Prefix Assigned |
| UPO | Blue-Shield of Northeastern New York |
| UPP | BCBS of Texas |
| UPQ | BCBS of Western New York |
| UPR | No Prefix Assigned |
| UPS | Wellmark BCBS |
| UPT | BCBS of Illinois |
| UPU | No Prefix Assigned |
| UPV | No Prefix Assigned |
| UPW | Anthem BCBS of Nevada |
| UPX | BCBS of Texas |
| UPY | BCBS of Alabama |
| UPZ | Blue-Shield of California |
| UQA | BCBS of Western New York |
| UQB | Wellmark BCBS |
| UQC | No Prefix Assigned |
| UQD | Wellmark BCBS |
| UQE | Anthem BCBS of Wisconsin |
| UQF | No Prefix Assigned |
| UQG | No Prefix Assigned |
| UQH | No Prefix Assigned |
| UQI | No Prefix Assigned |
| UQJ | No Prefix Assigned |
| UQK | Anthem BCBS of Connecticut |
| UQL | No Prefix Assigned |
| UQM | Anthem BCBS of Kentucky |
| UQN | No Prefix Assigned |
| UQO | Regence BCBS |
| UQP | Anthem BCBS of Ohio |
| UQQ | BCBS of Michigan |
| UQR | No Prefix Assigned |
| UQS | No Prefix Assigned |
| UQT | BCBS of Western New York |
| UQU | BCBS of Michigan |
| UQV | Anthem BCBS of Ohio |
| UQW | Horizon BCBS of New Jersey |
| UQX | BCBS of South Carolina |
| UQY | BCBS of Rhode Island |
| UQZ | BCBS of Rhode Island |
| URA | BCBS of Illinois |
| URB | No Prefix Assigned |
| URC | No Prefix Assigned |
| URD | No Prefix Assigned |
| URE | BCBS of Texas |
| URF | No Prefix Assigned |
| URG | No Prefix Assigned |
| URH | No Prefix Assigned |
| URI | Independence Blue Cross of Philadelphia/Southeastern Pennsylvania |
| URJ | Anthem BCBS of Nevada |
| URK | BCBS of Illinois |
| URL | Excellus BCBS of New York |
| URM | No Prefix Assigned |
| URN | BCBS of Illinois |
| URO | BCBS of Michigan |
| URP | BCBS of Michigan |
| URQ | Highmark BCBS of Pennsylvania |
| URR | BCBS of South Carolina |
| URS | Blue-Shield of California |
| URT | Blue-Shield of California |
| URU | BCBS of Michigan |
| URV | BCBS of Illinois |
| URW | Wellmark BCBS |
| URX | BCBS of Minnesota |
| URY | Anthem BCBS of Georgia |
| URZ | No Prefix Assigned |
| USA | Anthem Blue-Cross |
| USB | Regence BCBS |
| USC | No Prefix Assigned |
| USD | No Prefix Assigned |
| USE | BCBS of Texas |
| USF | No Prefix Assigned |
| USG | BCBS of Tennessee |
| USH | BCBS of Alabama |
| USI | No Prefix Assigned |
| USJ | Empire BCBS of New York |
| USK | BCBS of South Carolina |
| USL | No Prefix Assigned |
| USM | Blue-Shield of California |
| USN | BCBS of Tennessee |
| USO | Florida-Blue |
| USP | Anthem BCBS of Ohio |
| USQ | Anthem BCBS of Ohio |
| USR | Excellus BCBS of New York |
| USS | BCBS of North Carolina |
| UST | BCBS of Illinois |
| USU | Empire BCBS of New York |
| USV | Anthem BCBS of Ohio |
| USW | Highmark BCBS of Pennsylvania |
| USX | Empire BCBS of New York |
| USY | BCBS of South Carolina |
| USZ | No Prefix Assigned |
| UTA | Anthem BCBS of Ohio |
| UTB | Anthem BCBS of Virginia |
| UTC | Blue-Cross of Idaho |
| UTD | BCBS of Illinois |
| UTE | No Prefix Assigned |
| UTF | Independence Blue Cross of Philadelphia/Southeastern Pennsylvania |
| UTG | Anthem BCBS of Ohio |
| UTH | No Prefix Assigned |
| UTI | No Prefix Assigned |
| UTJ | No Prefix Assigned |
| UTK | BCBS of Arizona |
| UTL | BCBS of Illinois |
| UTM | Anthem Blue-Cross |
| UTN | BCBS of Illinois |
| UTO | Blue-Shield of California |
| UTP | No Prefix Assigned |
| UTQ | Independence Blue Cross of Philadelphia/Southeastern Pennsylvania |
| UTR | Independence Blue Cross of Philadelphia/Southeastern Pennsylvania |
| UTS | BCBS of Texas |
| UTT | Anthem BCBS of Ohio |
| UTU | Anthem BCBS of Georgia |
| UTV | BCBS of Illinois |
| UTW | No Prefix Assigned |
| UTX | Anthem BCBS of Connecticut |
| UTY | BCBS of Texas |
| UTZ | BCBS of Tennessee |
| UUA | Anthem BCBS of Georgia |
| UUB | No Prefix Assigned |
| UUC | BCBS of Oklahoma |
| UUD | No Prefix Assigned |
| UUE | Blue-Shield of California |
| UUF | BCBS of Illinois |
| UUG | Regence BCBS |
| UUH | Anthem BCBS of Missouri |
| UUI | BCBS of North Carolina |
| UUJ | No Prefix Assigned |
| UUK | Regence BCBS |
| UUL | BCBS of Tennessee |
| UUM | No Prefix Assigned |
| UUN | No Prefix Assigned |
| UUO | BCBS of Michigan |
| UUP | Anthem BCBS of Virginia |
| UUQ | No Prefix Assigned |
| UUR | No Prefix Assigned |
| UUS | Blue-Shield of California |
| UUT | No Prefix Assigned |
| UUU | No Prefix Assigned |
| UUV | No Prefix Assigned |
| UUW | No Prefix Assigned |
| UUX | BCBS of Illinois |
| UUY | No Prefix Assigned |
| UUZ | BCBS of Michigan |
| UVA | Anthem BCBS of Virginia |
| UVB | Anthem BCBS of Indiana |
| UVC | Independence Blue Cross of Philadelphia/Southeastern Pennsylvania |
| UVD | Anthem BCBS of Virginia |
| UVE | Independence Blue Cross of Philadelphia/Southeastern Pennsylvania |
| UVF | BCBS of Kansas City |
| UVG | Wellmark BCBS |
| UVH | No Prefix Assigned |
| UVI | BCBS of Michigan |
| UVJ | No Prefix Assigned |
| UVK | Carefirst BCBS |
| UVL | Independence Blue Cross of Philadelphia/Southeastern Pennsylvania |
| UVM | No Prefix Assigned |
| UVN | No Prefix Assigned |
| UVO | No Prefix Assigned |
| UVP | BCBS of Illinois |
| UVQ | No Prefix Assigned |
| UVR | No Prefix Assigned |
| UVS | BCBS of Illinois |
| UVT | Anthem BCBS of Virginia |
| UVU | BCBS of Alabama |
| UVV | Wellmark BCBS |
| UVW | Empire BCBS of New York |
| UVX | No Prefix Assigned |
| UVY | Anthem Blue-Cross |
| UVZ | BCBS of Texas |
| UWA | BCBS of Michigan |
| UWB | No Prefix Assigned |
| UWC | Anthem BCBS of Wisconsin |
| UWD | Anthem Blue-Cross |
| UWE | Anthem BCBS of Ohio |
| UWF | BCBS of Michigan |
| UWG | BCBS of Michigan |
| UWH | Anthem BCBS of Ohio |
| UWI | No Prefix Assigned |
| UWJ | No Prefix Assigned |
| UWK | No Prefix Assigned |
| UWL | No Prefix Assigned |
| UWM | Carefirst BCBS |
| UWN | BCBS of Illinois |
| UWO | No Prefix Assigned |
| UWP | BCBS of Rhode Island |
| UWQ | Empire BCBS of New York |
| UWR | No Prefix Assigned |
| UWS | Anthem BCBS of Connecticut |
| UWT | Horizon BCBS of New Jersey |
| UWU | BCBS of Tennessee |
| UWV | No Prefix Assigned |
| UWW | BCBS of Michigan |
| UWX | BCBS of Rhode Island |
| UWY | No Prefix Assigned |
| UWZ | No Prefix Assigned |
| UXA | No Prefix Assigned |
| UXB | BCBS of Alabama |
| UXC | Anthem Blue-Cross |
| UXD | BCBS of South Carolina |
| UXE | BCBS of Tennessee |
| UXF | Anthem Blue-Cross |
| UXG | BCBS of Michigan |
| UXH | Wellmark BCBS |
| UXI | Horizon BCBS of New Jersey |
| UXJ | BCBS of Illinois |
| UXK | No Prefix Assigned |
| UXL | Highmark BCBS of Pennsylvania |
| UXM | BCBS of Illinois |
| UXN | Blue-Shield of California |
| UXO | BCBS of Michigan |
| UXP | No Prefix Assigned |
| UXQ | Anthem BCBS of Missouri |
| UXR | Wellmark BCBS |
| UXS | Premera BCBS of Alaska |
| UXT | Anthem BCBS of Georgia |
| UXU | BCBS of Illinois |
| UXV | Anthem BCBS of Missouri |
| UXW | Horizon BCBS of New Jersey |
| UXX | BCBS of Michigan |
| UXY | Anthem BCBS of Missouri |
| UXZ | Anthem BCBS of Missouri |
| UYA | BCBS of Illinois |
| UYB | Anthem BCBS of Indiana |
| UYC | Empire BCBS of New York |
| UYD | No Prefix Assigned |
| UYE | BCBS of Massachusetts |
| UYF | Anthem Blue-Cross |
| UYG | Anthem BCBS of Virginia |
| UYH | Anthem BCBS of Indiana |
| UYI | BCBS of Michigan |
| UYJ | Regence BCBS |
| UYK | Anthem BCBS of Georgia |
| UYL | BCBS of Illinois |
| UYM | Carefirst BCBS |
| UYN | No Prefix Assigned |
| UYO | Anthem BCBS of Georgia |
| UYP | No Prefix Assigned |
| UYQ | BCBS of Louisiana |
| UYR | No Prefix Assigned |
| UYS | No Prefix Assigned |
| UYT | No Prefix Assigned |
| UYU | BCBS of Arizona |
| UYV | Wellmark BCBS |
| UYW | BCBS of Michigan |
| UYX | No Prefix Assigned |
| UYY | Anthem BCBS of Kentucky |
| UYZ | Blue-Cross of Idaho |
| UZA | No Prefix Assigned |
| UZB | Wellmark BCBS |
| UZC | Anthem Blue-Cross |
| UZD | Blue-Shield of California |
| UZE | Highmark BCBS of Pennsylvania |
| UZF | No Prefix Assigned |
| UZG | BCBS of Michigan |
| UZH | Wellmark BCBS |
| UZI | No Prefix Assigned |
| UZJ | No Prefix Assigned |
| UZK | Wellmark BCBS |
| UZL | No Prefix Assigned |
| UZM | BCBS of Louisiana |
| UZN | Florida-Blue |
| UZO | Anthem BCBS of Georgia |
| UZP | Anthem Blue-Cross |
| UZQ | Anthem BCBS of Connecticut |
| UZR | Carefirst BCBS |
| UZS | BCBS of Texas |
| UZT | Anthem BCBS of Colorado |
| UZU | No Prefix Assigned |
| UZV | BCBS of Michigan |
| UZW | BCBS of Michigan |
| UZX | No Prefix Assigned |
| UZY | BCBS of Michigan |
| UZZ | BCBS of Texas |
| U2A | BCBS of Texas |
| U2B | Empire BCBS |
| U2C | Empire BCBS |
| U2D | Empire BCBS |
| U2F | BCBS of Illinois |
| U2G | BCBS of Arkansas |
| U2H | Empire BCBS |
| U2J | Empire BCBS |
| U2M | BCBS of Oklahoma |
| U2N | Anthem BCBS of Indiana |
| U2P | Regence BCBS of Oregon |
| U2S | BCBS of Texas |
| U2T | Regence BCBS of Oregon |
| U2U | Regence BCBS of Oregon |
| U2W | Empire BCBS |
| U2Z | BCBS of Western New York |
| U3A | Blue Cross of California |
| U3B | Blue Cross of California |
| U3C | Blue Cross of California |
| U3D | Highmark BCBS of Pennsylvania |
| U3E | Highmark BCBS of Pennsylvania |
| U3F | Highmark BCBS of Pennsylvania |
| U3G | Highmark BCBS of Pennsylvania |
| U3N | Anthem BCBS of Indiana |
| U3P | BCBS of Massachusetts |
| U3U | BCBS of Illinois |
| U3V | BCBS of Illinois |
| U4B | Regence BCBS of Oregon |
| U4C | Empire BCBS |
| U4F | BCBS of Illinois |
| U4G | BCBS of Massachusetts |
| U4N | Anthem BCBS of Indiana |
| U4R | BCBS of Texas |
| U5A | BCBS of Alabama |
| U5N | Anthem BCBS of Indiana |
| U5P | BCBS of Alabama |
| U5R | BCBS of Texas |
| U6N | Anthem BCBS of Indiana |
| U6R | BCBS of Texas |
| U7P | Regence Blue Shield of Washington |
| U7R | BCBS of Texas |
| U8R | BCBS of Texas |
| U8S | BCBS of Massachusetts |
| U9A | Blue Cross of California |
| U9M | BCBS of Illinois |
| U9R | Premera Blue Cross |
