| WAA | BCBS of Alabama |
| WAB | BCBS of Illinois |
| WAC | Regence BCBS |
| WAD | Florida-Blue |
| WAE | BCBS of Texas |
| WAF | Premera BCBS of Alaska |
| WAG | BCBS of Illinois |
| WAH | Premera BCBS of Alaska |
| WAI | Regence BCBS |
| WAJ | Florida-Blue |
| WAK | Wellmark BCBS |
| WAL | BCBS of Massachusetts |
| WAM | Highmark BCBS of Pennsylvania |
| WAN | BCBS of Michigan |
| WAO | Blue-Shield of California |
| WAP | Carefirst BCBS |
| WAQ | Florida-Blue |
| WAR | No Prefix Assigned |
| WAS | No Prefix Assigned |
| WAT | BCBS of Rhode Island |
| WAU | Wellmark BCBS |
| WAV | BCBS of Massachusetts |
| WAW | BCBS of Massachusetts |
| WAX | Premera BCBS of Alaska |
| WAY | Horizon BCBS of New Jersey |
| WAZ | Premera BCBS of Alaska |
| WBA | BCBS of Illinois |
| WBB | Blue-Shield of California |
| WBC | Anthem BCBS of Virginia |
| WBD | BCBS of South Carolina |
| WBE | Blue-Cross of Idaho |
| WBF | Highmark BCBS of Pennsylvania |
| WBG | Regence BCBS |
| WBH | Anthem BCBS of Ohio |
| WBI | Anthem BCBS of Ohio |
| WBJ | Premera BCBS of Alaska |
| WBK | BCBS of North Carolina |
| WBL | Anthem BCBS of Kentucky |
| WBM | Wellmark BCBS |
| WBN | Anthem BCBS of Indiana |
| WBO | BCBS of Oklahoma |
| WBP | Regence BCBS |
| WBQ | BCBS of Michigan |
| WBR | No Prefix Assigned |
| WBS | Wellmark BCBS |
| WBT | Anthem BCBS of Ohio |
| WBU | BCBS of Michigan |
| WBV | BCBS of Texas |
| WBW | Anthem BCBS of Georgia |
| WBX | Blue-Shield of Northeastern New York |
| WBY | BCBS of Minnesota |
| WBZ | Anthem BCBS of Wisconsin |
| WCA | Anthem BCBS of Missouri |
| WCB | Wellmark BCBS |
| WCC | BCBS of Illinois |
| WCD | BCBS of Minnesota |
| WCE | Anthem Blue-Cross |
| WCF | No Prefix Assigned |
| WCG | Anthem BCBS of Ohio |
| WCH | BCBS of Massachusetts |
| WCI | Anthem BCBS of Wisconsin |
| WCJ | No Prefix Assigned |
| WCK | BCBS of Massachusetts |
| WCL | Premera BCBS of Alaska |
| WCM | Highmark BCBS of Pennsylvania |
| WCN | Regence BCBS |
| WCO | Capital Blue-Cross of Pennsylvania |
| WCP | Regence BCBS |
| WCQ | Wellmark BCBS |
| WCR | No Prefix Assigned |
| WCS | Anthem BCBS of Ohio |
| WCT | No Prefix Assigned |
| WCU | Anthem Blue-Cross |
| WCV | BCBS of Massachusetts |
| WCW | Blue-Shield of California |
| WCX | Wellmark BCBS |
| WCY | Regence BCBS |
| WCZ | Blue-Cross of Idaho |
| WDA | Carefirst BCBS |
| WDB | Anthem BCBS of Virginia |
| WDC | No Prefix Assigned |
| WDD | Arkansas BCBS |
| WDE | BCBS of Alabama |
| WDF | Carefirst BCBS |
| WDG | Blue-Shield of California |
| WDH | Wellmark BCBS |
| WDI | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| WDJ | No Prefix Assigned |
| WDK | No Prefix Assigned |
| WDL | No Prefix Assigned |
| WDM | BCBS of Nebraska |
| WDN | No Prefix Assigned |
| WDO | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| WDP | No Prefix Assigned |
| WDQ | Anthem BCBS of Ohio |
| WDR | No Prefix Assigned |
| WDS | Florida-Blue |
| WDT | No Prefix Assigned |
| WDU | Blue-Shield of California |
| WDV | No Prefix Assigned |
| WDW | No Prefix Assigned |
| WDX | Anthem BCBS of Virginia |
| WDY | No Prefix Assigned |
| WDZ | No Prefix Assigned |
| WEA | Anthem BCBS of Georgia |
| WEB | No Prefix Assigned |
| WEC | BCBS of Minnesota |
| WED | No Prefix Assigned |
| WEE | Wellmark BCBS |
| WEF | BCBS of Minnesota |
| WEG | BCBS of Texas |
| WEH | Wellmark BCBS |
| WEI | Wellmark BCBS |
| WEJ | Carefirst BCBS |
| WEK | Wellmark BCBS |
| WEL | BCBS of Massachusetts |
| WEM | Anthem Blue-Cross |
| WEN | No Prefix Assigned |
| WEO | Blue-Advantage of Arkansas |
| WEP | Anthem Blue-Cross |
| WEQ | BCBS of Nebraska |
| WER | No Prefix Assigned |
| WES | Arkansas BCBS |
| WET | Anthem Blue-Cross |
| WEU | No Prefix Assigned |
| WEV | BCBS of Western New York |
| WEW | No Prefix Assigned |
| WEX | No Prefix Assigned |
| WEY | No Prefix Assigned |
| WEZ | No Prefix Assigned |
| WFA | Highmark BCBS of Pennsylvania |
| WFB | Carefirst BCBS |
| WFC | Blue-Cross of Idaho |
| WFD | Anthem Blue-Cross |
| WFE | Regence BCBS |
| WFF | No Prefix Assigned |
| WFG | Regence BCBS |
| WFH | Anthem BCBS of Missouri |
| WFI | Empire BCBS of New York |
| WFJ | Carefirst BCBS |
| WFK | No Prefix Assigned |
| WFL | Anthem BCBS of Georgia |
| WFM | Excellus BCBS of New York |
| WFN | No Prefix Assigned |
| WFO | BCBS of Tennessee |
| WFP | No Prefix Assigned |
| WFQ | Anthem BCBS of Indiana |
| WFR | No Prefix Assigned |
| WFS | Empire BCBS of New York |
| WFT | Premera BCBS of Alaska |
| WFU | BCBS of South Carolina |
| WFV | Carefirst BCBS |
| WFW | Highmark BCBS of Pennsylvania |
| WFX | Premera BCBS of Alaska |
| WFY | Carefirst BCBS |
| WFZ | Excellus BCBS of New York |
| WGA | No Prefix Assigned |
| WGB | Blue-Cross of Idaho |
| WGC | BCBS of Massachusetts |
| WGD | No Prefix Assigned |
| WGE | BCBS of Alabama |
| WGF | Anthem Blue-Cross |
| WGG | No Prefix Assigned |
| WGH | Wellmark BCBS |
| WGI | BCBS of Michigan |
| WGJ | Carefirst BCBS |
| WGK | No Prefix Assigned |
| WGL | Anthem BCBS of Georgia |
| WGM | No Prefix Assigned |
| WGN | Excellus BCBS of New York |
| WGO | Blue-Shield of California |
| WGP | Wellmark BCBS |
| WGQ | Anthem BCBS of New Hampshire |
| WGR | Wellmark BCBS |
| WGS | No Prefix Assigned |
| WGT | BCBS of Western New York |
| WGU | No Prefix Assigned |
| WGV | No Prefix Assigned |
| WGW | Anthem BCBS of Missouri |
| WGX | Arkansas BCBS |
| WGY | No Prefix Assigned |
| WGZ | BCBS of Illinois |
| WHA | Anthem BCBS of Virginia |
| WHB | BCBS of Massachusetts |
| WHC | BCBS of Michigan |
| WHD | BCBS of Michigan |
| WHE | Carefirst BCBS |
| WHF | Wellmark BCBS |
| WHG | Blue-Cross of Idaho |
| WHH | Wellmark BCBS |
| WHI | Empire BCBS of New York |
| WHJ | BCBS of Massachusetts |
| WHK | Anthem BCBS of Virginia |
| WHL | BCBS of Western New York |
| WHM | Blue-Advantage of Arkansas |
| WHN | BCBS of Michigan |
| WHO | BCBS of Michigan |
| WHP | Carefirst BCBS |
| WHQ | Highmark BCBS of Pennsylvania |
| WHR | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| WHS | BCBS of Illinois |
| WHT | BCBS of Massachusetts |
| WHU | Wellmark BCBS |
| WHV | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| WHW | BCBS of Minnesota |
| WHX | BCBS of Massachusetts |
| WHY | Anthem BCBS of Indiana |
| WHZ | Anthem BCBS of Georgia |
| WIA | Anthem BCBS of Virginia |
| WIB | BCBS of South Carolina |
| WIC | No Prefix Assigned |
| WID | BCBS of Michigan |
| WIE | Arkansas BCBS |
| WIF | BCBS of North Carolina |
| WIG | Anthem BCBS of Wisconsin |
| WIH | Premera Blue-Cross of Alaska |
| WII | No Prefix Assigned |
| WIJ | Anthem BCBS of Georgia |
| WIK | Blue-Shield of California |
| WIL | BCBS of Alabama |
| WIM | Blue-Shield of California |
| WIN | Wellmark BCBS |
| WIO | Blue-Shield of California |
| WIP | Regence BCBS |
| WIQ | Anthem BCBS of Georgia |
| WIR | No Prefix Assigned |
| WIS | No Prefix Assigned |
| WIT | No Prefix Assigned |
| WIU | Anthem BCBS of Wisconsin |
| WIV | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| WIW | Anthem BCBS of Georgia |
| WIX | Anthem BCBS of Georgia |
| WIY | BCBS of Kansas City |
| WIZ | No Prefix Assigned |
| WJA | Premera BCBS of Alaska |
| WJB | No Prefix Assigned |
| WJC | No Prefix Assigned |
| WJD | Anthem BCBS of Georgia |
| WJE | Anthem BCBS of Indiana |
| WJF | BCBS of Illinois |
| WJG | BCBS of Massachusetts |
| WJH | Carefirst BCBS |
| WJI | Highmark BCBS of Pennsylvania |
| WJJ | Carefirst BCBS |
| WJK | Capital Blue-Cross of Pennsylvania |
| WJL | BCBS of Nebraska |
| WJM | Wellmark BCBS |
| WJN | No Prefix Assigned |
| WJO | Highmark BCBS of Pennsylvania |
| WJP | Anthem BCBS of Wisconsin |
| WJQ | No Prefix Assigned |
| WJR | Anthem BCBS of Virginia |
| WJS | Anthem BCBS of Ohio |
| WJT | Anthem BCBS of Missouri |
| WJU | Wellmark BCBS |
| WJV | BCBS of Texas |
| WJW | BCBS of Illinois |
| WJX | BCBS of Illinois |
| WJY | BCBS of Illinois |
| WJZ | BCBS of Massachusetts |
| WKA | Anthem BCBS of Ohio |
| WKB | No Prefix Assigned |
| WKC | Capital Blue-Cross of Pennsylvania |
| WKD | BCBS of Alabama |
| WKE | No Prefix Assigned |
| WKF | Anthem Blue-Cross |
| WKG | No Prefix Assigned |
| WKH | Anthem Blue-Cross |
| WKI | Regence BCBS |
| WKJ | Anthem BCBS of Ohio |
| WKK | BCBS of Illinois |
| WKL | Premera BCBS of Alaska |
| WKM | No Prefix Assigned |
| WKN | No Prefix Assigned |
| WKO | No Prefix Assigned |
| WKP | Capital Blue-Cross of Pennsylvania |
| WKQ | BCBS of North Carolina |
| WKR | Anthem BCBS of Wisconsin |
| WKS | BCBS of Massachusetts |
| WKT | Anthem BCBS of Wisconsin |
| WKU | BCBS of North Carolina |
| WKV | No Prefix Assigned |
| WKW | BCBS of Massachusetts |
| WKX | Anthem BCBS of Wisconsin |
| WKY | BCBS of Illinois |
| WKZ | Anthem BCBS of Wisconsin |
| WLA | No Prefix Assigned |
| WLB | BCBS of South Carolina |
| WLC | BCBS of Texas |
| WLD | No Prefix Assigned |
| WLE | BCBS of Michigan |
| WLF | BCBS of Illinois |
| WLG | BCBS of Alabama |
| WLH | Blue-Shield of California |
| WLI | Anthem BCBS of Ohio |
| WLJ | Premera BCBS of Alaska |
| WLK | Blue-Cross of Idaho |
| WLL | Anthem BCBS of Kentucky |
| WLM | BCBS of Illinois |
| WLN | Highmark BCBS of Delaware |
| WLO | No Prefix Assigned |
| WLP | Anthem Blue-Cross |
| WLQ | Wellmark BCBS |
| WLR | Empire BCBS of New York |
| WLS | BCBS of Alabama |
| WLT | Wellmark BCBS |
| WLU | Anthem BCBS of Indiana |
| WLV | No Prefix Assigned |
| WLW | Wellmark BCBS |
| WLX | Wellmark BCBS |
| WLY | No Prefix Assigned |
| WLZ | Highmark BCBS of Delaware |
| WMA | Wellmark BCBS |
| WMB | Anthem BCBS of Missouri |
| WMC | BCBS of Minnesota |
| WMD | BCBS of Minnesota |
| WME | BCBS of Illinois |
| WMF | Wellmark BCBS |
| WMG | Anthem Blue-Cross |
| WMH | Highmark BCBS of Delaware |
| WMI | BCBS of Michigan |
| WMJ | Arkansas BCBS |
| WMK | Capital Blue-Cross of Pennsylvania |
| WML | Anthem BCBS of Wisconsin |
| WMM | BCBS of Minnesota |
| WMN | BCBS of Illinois |
| WMO | Anthem Blue-Cross |
| WMP | BCBS of Minnesota |
| WMQ | No Prefix Assigned |
| WMR | Anthem BCBS of Indiana |
| WMS | Anthem BCBS of Indiana |
| WMT | Anthem Blue-Cross |
| WMU | BCBS of Texas |
| WMV | BCBS of Tennessee |
| WMW | Arkansas BCBS |
| WMX | Anthem BCBS of Indiana |
| WMY | Arkansas BCBS |
| WMZ | Anthem BCBS of Indiana |
| WNA | Anthem BCBS of Indiana |
| WNB | Empire BCBS of New York |
| WNC | BCBS of Alabama |
| WND | Excellus BCBS of New York |
| WNE | Premera BCBS of Alaska |
| WNF | Anthem Blue-Cross |
| WNG | Anthem BCBS of Wisconsin |
| WNH | Empire BCBS of New York |
| WNI | Regence BCBS |
| WNJ | No Prefix Assigned |
| WNK | Arkansas BCBS |
| WNL | Carefirst BCBS |
| WNM | BCBS of Western New York |
| WNN | No Prefix Assigned |
| WNO | No Prefix Assigned |
| WNP | No Prefix Assigned |
| WNQ | BCBS of Michigan |
| WNR | Anthem BCBS of Georgia |
| WNS | BCBS of Illinois |
| WNT | BCBS of Illinois |
| WNU | No Prefix Assigned |
| WNV | No Prefix Assigned |
| WNW | BCBS of Massachusetts |
| WNX | Arkansas BCBS |
| WNY | No Prefix Assigned |
| WNZ | BCBS of Massachusetts |
| WOA | Anthem Blue-Cross |
| WOB | Premera BCBS of Alaska |
| WOC | No Prefix Assigned |
| WOD | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| WOE | No Prefix Assigned |
| WOF | BCBS of Michigan |
| WOG | No Prefix Assigned |
| WOH | Highmark BCBS of Pennsylvania |
| WOI | No Prefix Assigned |
| WOJ | Arkansas BCBS |
| WOK | BCBS of South Carolina |
| WOL | Blue-Shield of Northeastern New York |
| WOM | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| WON | No Prefix Assigned |
| WOO | BCBS of Michigan |
| WOP | BCBS of Michigan |
| WOQ | BCBS of Michigan |
| WOR | No Prefix Assigned |
| WOS | No Prefix Assigned |
| WOT | BCBS of Michigan |
| WOU | No Prefix Assigned |
| WOV | Anthem BCBS of Georgia |
| WOW | Premera BCBS of Alaska |
| WOX | No Prefix Assigned |
| WOY | BCBS of Michigan |
| WOZ | Anthem BCBS of Colorado |
| WPA | Arkansas BCBS |
| WPB | Capital Blue-Cross of Pennsylvania |
| WPC | BCBS of Kansas City |
| WPD | Anthem BCBS of Ohio |
| WPE | No Prefix Assigned |
| WPF | BCBS of Rhode Island |
| WPG | BCBS of Kansas City |
| WPH | BCBS of Alabama |
| WPI | BCBS of Michigan |
| WPJ | No Prefix Assigned |
| WPK | Anthem Blue-Cross |
| WPL | Anthem BCBS of Ohio |
| WPM | BCBS of Kansas City |
| WPN | No Prefix Assigned |
| WPO | BCBS of Michigan |
| WPP | Anthem BCBS of Kentucky |
| WPQ | Anthem BCBS of Colorado |
| WPR | Empire BCBS of New York |
| WPS | Arkansas BCBS |
| WPT | Wellmark BCBS |
| WPU | Anthem Blue-Cross |
| WPV | Anthem Blue-Cross |
| WPW | Anthem BCBS of Indiana |
| WPX | Anthem Blue-Cross |
| WPY | Anthem Blue-Cross |
| WPZ | Wellmark BCBS |
| WQA | No Prefix Assigned |
| WQB | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| WQC | No Prefix Assigned |
| WQD | BCBS of Western New York |
| WQE | Highmark BCBS of Pennsylvania |
| WQF | No Prefix Assigned |
| WQG | Highmark BCBS of Pennsylvania |
| WQH | Highmark BCBS of Pennsylvania |
| WQI | Highmark BCBS of Pennsylvania |
| WQJ | BCBS of Western New York |
| WQK | No Prefix Assigned |
| WQL | No Prefix Assigned |
| WQM | No Prefix Assigned |
| WQN | BCBS of Illinois |
| WQO | BCBS of Western New York |
| WQP | Anthem BCBS of Ohio |
| WQQ | BCBS of Western New York |
| WQR | Highmark BCBS of Pennsylvania |
| WQS | No Prefix Assigned |
| WQT | No Prefix Assigned |
| WQU | Anthem BCBS of Ohio |
| WQV | No Prefix Assigned |
| WQW | Wellmark BCBS |
| WQX | No Prefix Assigned |
| WQY | Anthem BCBS of Ohio |
| WQZ | Wellmark BCBS |
| WRA | Wellmark BCBS |
| WRB | No Prefix Assigned |
| WRC | Horizon BCBS of New Jersey |
| WRD | No Prefix Assigned |
| WRE | Anthem BCBS of Kentucky |
| WRF | BCBS of Massachusetts |
| WRG | Anthem BCBS of Ohio |
| WRH | No Prefix Assigned |
| WRI | BCBS of Alabama |
| WRJ | No Prefix Assigned |
| WRK | BCBS of Rhode Island |
| WRL | Regence BCBS |
| WRM | Highmark BCBS of Pennsylvania |
| WRN | Regence BCBS |
| WRO | Anthem BCBS of Georgia |
| WRP | No Prefix Assigned |
| WRQ | Anthem BCBS of Georgia |
| WRR | Anthem BCBS of Missouri |
| WRS | Anthem Blue-Cross |
| WRT | No Prefix Assigned |
| WRU | Wellmark BCBS |
| WRV | BCBS of Alabama |
| WRW | BCBS of Rhode Island |
| WRX | Anthem Blue-Cross |
| WRY | Anthem BCBS of Georgia |
| WRZ | Anthem BCBS of Georgia |
| WSA | Blue-Advantage of Arkansas |
| WSB | BCBS of Minnesota |
| WSC | BCBS of Illinois |
| WSD | Anthem BCBS of Wisconsin |
| WSE | No Prefix Assigned |
| WSF | Arkansas BCBS |
| WSG | Anthem BCBS of Ohio |
| WSH | No Prefix Assigned |
| WSI | BCBS of North Carolina |
| WSJ | Anthem Blue-Cross |
| WSK | Anthem BCBS of Nevada |
| WSL | Wellmark BCBS |
| WSM | Anthem BCBS of Wisconsin |
| WSN | BCBS of South Carolina |
| WSO | Anthem BCBS of Ohio |
| WSP | Anthem BCBS of Indiana |
| WSQ | No Prefix Assigned |
| WSR | No Prefix Assigned |
| WSS | BCBS of Western New York |
| WST | BCBS of Massachusetts |
| WSU | Wellmark BCBS |
| WSV | Wellmark BCBS |
| WSW | BCBS of Illinois |
| WSX | BCBS of Minnesota |
| WSY | Anthem BCBS of Ohio |
| WSZ | BCBS of Illinois |
| WTA | Anthem BCBS of Wisconsin |
| WTB | Wellmark BCBS |
| WTC | Premera BCBS of Alaska |
| WTD | BCBS of Western New York |
| WTE | BCBS of Illinois |
| WTF | No Prefix Assigned |
| WTG | Regence BCBS |
| WTH | BCBS of Illinois |
| WTI | No Prefix Assigned |
| WTJ | No Prefix Assigned |
| WTK | No Prefix Assigned |
| WTL | No Prefix Assigned |
| WTM | BCBS of Illinois |
| WTN | Wellmark BCBS |
| WTO | Arkansas BCBS |
| WTP | Carefirst BCBS |
| WTQ | BCBS of Alabama |
| WTR | BCBS of Illinois |
| WTS | Anthem BCBS of Wisconsin |
| WTT | Premera BCBS of Alaska |
| WTU | Premera BCBS of Alaska |
| WTV | Premera BCBS of Alaska |
| WTW | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| WTX | No Prefix Assigned |
| WTY | No Prefix Assigned |
| WTZ | BCBS of Illinois |
| WUA | BCBS of Michigan |
| WUB | BCBS of Texas |
| WUC | Empire BCBS of New York |
| WUD | No Prefix Assigned |
| WUE | Blue-Shield of California |
| WUF | Wellmark BCBS |
| WUG | Horizon BCBS of New Jersey |
| WUH | Carefirst BCBS |
| WUI | Anthem BCBS of Ohio |
| WUJ | BCBS of Rhode Island |
| WUK | Anthem BCBS of Indiana |
| WUL | Anthem BCBS of Indiana |
| WUM | Highmark BCBS of Pennsylvania |
| WUN | BCBS of North Carolina |
| WUO | Blue-Shield of California |
| WUP | No Prefix Assigned |
| WUQ | Wellmark BCBS |
| WUR | Horizon BCBS of New Jersey |
| WUS | Anthem BCBS of Colorado |
| WUT | Anthem BCBS of Indiana |
| WUU | BCBS of South Carolina |
| WUV | BCBS of Massachusetts |
| WUW | Anthem Blue-Cross |
| WUX | Anthem BCBS of Indiana |
| WUY | No Prefix Assigned |
| WUZ | No Prefix Assigned |
| WVA | Blue-Cross of Idaho |
| WVB | No Prefix Assigned |
| WVC | Anthem BCBS of Wisconsin |
| WVD | Florida-Blue |
| WVE | BCBS of Illinois |
| WVF | No Prefix Assigned |
| WVG | No Prefix Assigned |
| WVH | Highmark BCBS of West Virginia |
| WVI | Blue-Shield of California |
| WVJ | No Prefix Assigned |
| WVK | BCBS of North Carolina |
| WVL | BCBS of Alabama |
| WVM | Wellmark BCBS |
| WVN | No Prefix Assigned |
| WVO | Arkansas BCBS |
| WVP | Carefirst BCBS |
| WVQ | No Prefix Assigned |
| WVR | Anthem BCBS of Georgia |
| WVS | Blue-Shield of California |
| WVT | Highmark BCBS of Pennsylvania |
| WVU | Anthem BCBS of Kentucky |
| WVV | No Prefix Assigned |
| WVW | No Prefix Assigned |
| WVX | Blue-Cross of Idaho |
| WVY | Anthem BCBS of Colorado |
| WVZ | Wellmark BCBS |
| WWA | Empire BCBS of New York |
| WWB | BCBS of Massachusetts |
| WWC | BCBS of Massachusetts |
| WWD | Regence BCBS |
| WWE | Wellmark BCBS |
| WWF | BCBS of Texas |
| WWG | No Prefix Assigned |
| WWH | No Prefix Assigned |
| WWI | Premera BCBS of Alaska |
| WWJ | No Prefix Assigned |
| WWK | No Prefix Assigned |
| WWL | No Prefix Assigned |
| WWM | Blue-Advantage of Arkansas |
| WWN | BCBS of Nebraska |
| WWO | Carefirst BCBS |
| WWP | Anthem Blue-Cross |
| WWQ | Anthem BCBS of Wisconsin |
| WWR | Wellmark BCBS |
| WWS | Anthem Blue-Cross |
| WWT | Carefirst BCBS |
| WWU | BCBS of Massachusetts |
| WWV | BCBS of Texas |
| WWW | Carefirst BCBS |
| WWX | Carefirst BCBS |
| WWY | BCBS of Massachusetts |
| WWZ | BCBS of Michigan |
| WXA | Anthem BCBS of Wisconsin |
| WXB | Wellmark BCBS |
| WXC | BCBS of Texas |
| WXD | BCBS of Texas |
| WXE | BCBS of Nebraska |
| WXF | BCBS of Texas |
| WXG | BCBS of Texas |
| WXH | BCBS of South Carolina |
| WXI | No Prefix Assigned |
| WXJ | Regence BCBS |
| WXK | Wellmark BCBS |
| WXL | BCBS of Minnesota |
| WXM | Highmark BCBS of Pennsylvania |
| WXN | BCBS of Illinois |
| WXO | Anthem BCBS of Colorado |
| WXP | Anthem BCBS of Missouri |
| WXQ | Wellmark BCBS |
| WXR | BCBS of Texas |
| WXS | BCBS of Tennessee |
| WXT | No Prefix Assigned |
| WXU | BCBS of Texas |
| WXV | No Prefix Assigned |
| WXW | No Prefix Assigned |
| WXX | BCBS of Texas |
| WXY | Anthem Blue-Cross |
| WXZ | Florida-Blue |
| WYA | No Prefix Assigned |
| WYB | BCBS of Illinois |
| WYC | Anthem Blue-Cross |
| WYD | No Prefix Assigned |
| WYE | Horizon BCBS of New Jersey |
| WYF | Wellmark BCBS |
| WYG | Anthem BCBS of Ohio |
| WYH | BCBS of Illinois |
| WYI | BCBS of Michigan |
| WYJ | No Prefix Assigned |
| WYK | Anthem BCBS of Virginia |
| WYL | No Prefix Assigned |
| WYM | BCBS of Illinois |
| WYN | No Prefix Assigned |
| WYO | BCBS of Michigan |
| WYP | No Prefix Assigned |
| WYQ | No Prefix Assigned |
| WYR | Arkansas BCBS |
| WYS | BCBS of Alabama |
| WYT | Carefirst BCBS |
| WYU | BCBS of Illinois |
| WYV | No Prefix Assigned |
| WYW | Blue-Cross of Idaho |
| WYX | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| WYY | BCBS of Oklahoma |
| WYZ | Florida-Blue |
| WZA | No Prefix Assigned |
| WZB | Anthem BCBS of Wisconsin |
| WZC | Wellmark BCBS |
| WZD | Anthem BCBS of Wisconsin |
| WZE | No Prefix Assigned |
| WZF | Carefirst BCBS |
| WZG | BCBS of Texas |
| WZH | Premera BCBS of Alaska |
| WZI | Blue-Shield of California |
| WZJ | No Prefix Assigned |
| WZK | No Prefix Assigned |
| WZL | Anthem BCBS of Wisconsin |
| WZM | Anthem BCBS of Ohio |
| WZN | Wellmark BCBS |
| WZO | Regence BCBS |
| WZP | Anthem BCBS of Wisconsin |
| WZQ | Regence BCBS |
| WZR | Anthem BCBS of Colorado |
| WZS | Anthem BCBS of Colorado |
| WZT | Anthem BCBS of Colorado |
| WZU | Anthem BCBS of Wisconsin |
| WZV | Anthem BCBS of Wisconsin |
| WZW | Florida-Blue |
| WZX | Wellmark BCBS |
| WZY | Anthem BCBS of Ohio |
| WZZ | BCBS of Minnesota |
| W2A | Blue Shield of Northeastern New York |
| W2B | BCBS of Illinois |
| W2C | Anthem BCBS of Georgia |
| W2E | Anthem BCBS of Colorado |
| W2F | BCBS of Illinois |
| W2G | Regence BCBS of Oregon |
| W2I | Anthem BCBS of Virginia |
| W2K | BCBS of Arkansas |
| W2L | BCBS of Illinois |
| W2M | BCBS of Illinois |
| W2N | BCBS of Arkansas |
| W2P | Regence BCBS of Oregon |
| W2S | Regence Blue Shield of Washington |
| W2T | Regence BCBS of Oregon |
| W2W | BCBS of Arkansas |
| W3A | Highmark BCBS of Pennsylvania |
| W3C | Regence Blue Shield of Washington |
| W3E | Blue Cross of California |
| W3H | Premera Blue Cross |
| W3K | Premera Blue Cross |
| W3M | BCBS of Illinois |
| W3P | Empire BCBS |
| W3T | BCBS of Arkansas |
| W3W | Empire BCBS |
| W3X | Empire BCBS |
| W4F | BCBS of Texas |
| W4G | BCBS of Texas |
| W4J | BCBS of Texas |
| W4K | BCBS of Texas |
| W4M | BCBS of Texas |
| W4N | BCBS of Texas |
| W4P | BCBS of Texas |
| W4R | BCBS of Texas |
| W4T | Premera Blue Cross |
| W4V | BCBS of Texas |
| W4W | BCBS of Texas |
| W4X | BCBS of Texas |
| W4Y | BCBS of Texas |
| W4Z | BCBS of Texas |
| W5H | Premera Blue Cross |
| W5M | BCBS of Illinois |
| W5T | Premera Blue Cross |
| W6A | BCBS of Texas |
| W7H | BCBS of Illinois |
| W8A | Anthem BCBS of Wisconsin |
| W8B | Anthem BCBS of Wisconsin |
