| SAA | Wellmark BCBS |
| SAB | Anthem BCBS of Ohio |
| SAC | Anthem Blue-Cross |
| SAD | BCBS of North Carolina |
| SAE | Anthem BCBS of Virginia |
| SAF | Anthem Blue-Cross |
| SAG | Anthem Blue-Cross |
| SAH | BCBS of Illinois |
| SAI | Anthem BCBS of Ohio |
| SAJ | Blue-Shield of California |
| SAK | BCBS of Illinois |
| SAL | BCBS of South Carolina |
| SAM | Carefirst BCBS |
| SAN | Anthem BCBS of Virginia |
| SAO | Wellmark BCBS |
| SAP | Blue-Shield of California |
| SAQ | BCBS of Minnesota |
| SAR | BCBS of Michigan |
| SAS | Capital Blue-Cross of Pennsylvania |
| SAT | Wellmark BCBS |
| SAU | BCBS of South Carolina |
| SAV | No prefix Assigned |
| SAW | Regence BCBS |
| SAX | Empire BCBS of New York |
| SAY | Carefirst BCBS |
| SAZ | No prefix Assigned |
| SBA | Anthem BCBS of Indiana |
| SBB | Anthem BCBS of Missouri |
| SBC | BCBS of Illinois |
| SBD | BCBS of South Carolina |
| SBE | BCBS of Massachusetts |
| SBF | BCBS of Illinois |
| SBG | No prefix Assigned |
| SBH | Highmark BCBS of Pennsylvania |
| SBI | Anthem BCBS of Georgia |
| SBJ | No prefix Assigned |
| SBK | Carefirst BCBS |
| SBL | No prefix Assigned |
| SBM | No prefix Assigned |
| SBN | Carefirst BCBS |
| SBO | No prefix Assigned |
| SBP | BCBS of Texas |
| SBQ | BCBS of Illinois |
| SBR | Highmark BCBS of Pennsylvania |
| SBS | Anthem BCBS of Georgia |
| SBT | Anthem BCBS of Ohio |
| SBU | Premera BCBS of Alaska |
| SBV | Anthem Blue-Cross |
| SBW | BCBS of Massachusetts |
| SBX | BCBS of Massachusetts |
| SBY | BCBS of Kansas City |
| SBZ | No prefix Assigned |
| SCA | Regence BCBS |
| SCB | BCBS of South Carolina |
| SCC | Blue-Shield of California |
| SCD | BCBS of Texas |
| SCE | BCBS of Illinois |
| SCF | Anthem BCBS of Virginia |
| SCG | BCBS of Alabama |
| SCH | BCBS of Minnesota |
| SCI | Regence BCBS |
| SCJ | BCBS of Minnesota |
| SCK | Wellmark BCBS |
| SCL | Premera BCBS of Alaska |
| SCM | BCBS of Texas |
| SCN | Anthem BCBS of Ohio |
| SCO | BCBS of Alabama |
| SCP | Credence BCBS |
| SCQ | Wellmark BCBS |
| SCR | BCBS of Michigan |
| SCS | Capital Blue-Cross of Pennsylvania |
| SCT | Anthem BCBS of Virginia |
| SCU | Blue-Cross of Idaho |
| SCV | Horizon BCBS of New Jersey |
| SCW | BCBS of Alabama |
| SCX | BCBS of Illinois |
| SCY | BCBS of Alabama |
| SCZ | BCBS of South Carolina |
| SDA | BCBS of Nebraska |
| SDB | BCBS of South Carolina |
| SDC | Anthem BCBS of Virginia |
| SDD | Blue-Shield of Northeastern New York |
| SDE | Highmark BCBS of Delaware |
| SDF | Wellmark BCBS |
| SDG | Anthem Blue-Cross |
| SDH | Wellmark BCBS |
| SDI | No prefix Assigned |
| SDJ | BCBS of Minnesota |
| SDK | BCBS of South Carolina |
| SDL | BCBS of South Carolina |
| SDM | No prefix Assigned |
| SDN | Anthem BCBS of Connecticut |
| SDO | BCBS of Illinois |
| SDP | Empire BCBS of New York |
| SDQ | Horizon BCBS of New Jersey |
| SDR | Highmark BCBS of Pennsylvania |
| SDS | Excellus BCBS of New York |
| SDT | BCBS of Alabama |
| SDU | Anthem Blue-Cross |
| SDV | Anthem BCBS of Ohio |
| SDW | BCBS of Oklahoma |
| SDX | BCBS of Minnesota |
| SDY | Florida-Blue |
| SDZ | No prefix Assigned |
| SEA | Premera BCBS of Alaska |
| SEB | BCBS of Michigan |
| SEC | Florida-Blue |
| SED | BCBS of Illinois |
| SEE | BCBS of Michigan |
| SEF | No prefix Assigned |
| SEG | Anthem BCBS of Kentucky |
| SEH | BCBS of Alabama |
| SEI | Highmark BCBS of Pennsylvania |
| SEJ | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| SEK | BCBS of South Carolina |
| SEL | Wellmark BCBS |
| SEM | Anthem BCBS of Virginia |
| SEN | Anthem BCBS of Indiana |
| SEO | Blue-Shield of California |
| SEP | Capital Blue-Cross of Pennsylvania |
| SEQ | No prefix Assigned |
| SER | Anthem BCBS of Virginia |
| SES | BCBS of Michigan |
| SET | BCBS of Texas |
| SEU | Wellmark BCBS |
| SEV | BCBS of North Carolina |
| SEW | BCBS of Tennessee |
| SEX | No prefix Assigned |
| SEY | Anthem Blue-Cross |
| SEZ | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| SFA | Empire BCBS of New York |
| SFB | BCBS of Illinois |
| SFC | Wellmark BCBS |
| SFD | No prefix Assigned |
| SFE | No prefix Assigned |
| SFF | BCBS of Tennessee |
| SFG | Blue-Shield of California |
| SFH | Wellmark BCBS |
| SFI | BCBS of Illinois |
| SFJ | Wellmark BCBS |
| SFK | Anthem BCBS of Ohio |
| SFL | Florida-Blue |
| SFM | BCBS of Alabama |
| SFN | Wellmark BCBS |
| SFO | BCBS of Massachusetts |
| SFP | BCBS of Illinois |
| SFQ | BCBS of Mississippi |
| SFR | BCBS of South Carolina |
| SFS | BCBS of Tennessee |
| SFT | Arkansas BCBS |
| SFU | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| SFV | Anthem BCBS of Virginia |
| SFW | Empire BCBS of New York |
| SFX | Anthem BCBS of Missouri |
| SFY | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| SFZ | BCBS of Illinois |
| SGA | BCBS of South Carolina |
| SGB | BCBS of Michigan |
| SGC | BCBS of Michigan |
| SGD | No prefix Assigned |
| SGE | Anthem Blue-Cross |
| SGF | Anthem BCBS of Kentucky |
| SGG | BCBS of Illinois |
| SGH | Horizon BCBS of New Jersey |
| SGI | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| SGJ | Blue-Cross of Idaho |
| SGK | No prefix Assigned |
| SGL | Regence BCBS |
| SGM | BCBS of Michigan |
| SGN | BCBS of Louisiana |
| SGO | BCBS of Massachusetts |
| SGP | Carefirst BCBS |
| SGQ | No prefix Assigned |
| SGR | BCBS of Massachusetts |
| SGS | BCBS of South Carolina |
| SGT | BCBS of Massachusetts |
| SGU | Florida-Blue |
| SGV | Anthem Blue-Cross |
| SGW | BCBS of Illinois |
| SGX | Horizon BCBS of New Jersey |
| SGY | Anthem BCBS of Ohio |
| SGZ | Horizon BCBS of New Jersey |
| SHA | Anthem BCBS of Missouri |
| SHB | Anthem BCBS of Ohio |
| SHC | Anthem Blue-Cross |
| SHD | Empire BCBS of New York |
| SHE | Wellmark BCBS |
| SHF | Anthem BCBS of Missouri |
| SHG | Capital Blue-Cross of Pennsylvania |
| SHH | BCBS of Kansas City |
| SHI | Wellmark BCBS |
| SHJ | No prefix Assigned |
| SHK | BCBS of Alabama |
| SHL | Anthem BCBS of Georgia |
| SHM | Empire BCBS of New York |
| SHN | BCBS of Illinois |
| SHO | Anthem Blue-Cross |
| SHP | Anthem BCBS of Connecticut |
| SHQ | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| SHR | BCBS of Massachusetts |
| SHS | Carefirst BCBS |
| SHT | BCBS of Texas |
| SHU | No prefix Assigned |
| SHV | No prefix Assigned |
| SHW | Anthem BCBS of Virginia |
| SHX | BCBS of Louisiana |
| SHY | No prefix Assigned |
| SHZ | BCBS of North Dakota |
| SIA | Wellmark BCBS |
| SIB | BCBS of South Carolina |
| SIC | Blue-Shield of California |
| SID | Regence BCBS |
| SIE | No prefix Assigned |
| SIF | Anthem Blue-Cross |
| SIG | BCBS of Massachusetts |
| SIH | Empire BCBS of New York |
| SII | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| SIJ | Anthem BCBS of Georgia |
| SIK | No prefix Assigned |
| SIL | Blue-Shield of California |
| SIM | Arkansas BCBS |
| SIN | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| SIO | BCBS of North Carolina |
| SIP | No prefix Assigned |
| SIQ | No prefix Assigned |
| SIR | Anthem Blue-Cross |
| SIS | No prefix Assigned |
| SIT | Anthem BCBS of Ohio |
| SIU | BCBS of Illinois |
| SIV | Blue-Shield of California |
| SIW | BCBS of Illinois |
| SIX | No prefix Assigned |
| SIY | Anthem BCBS of Ohio |
| SIZ | Wellmark BCBS |
| SJA | Anthem BCBS of Ohio |
| SJB | Anthem BCBS of Ohio |
| SJC | Florida-Blue |
| SJD | Carefirst BCBS |
| SJE | Anthem BCBS of Ohio |
| SJF | Anthem BCBS of Ohio |
| SJG | Anthem BCBS of Connecticut |
| SJH | Anthem BCBS of Ohio |
| SJI | BCBS of Louisiana |
| SJJ | No prefix Assigned |
| SJK | Arkansas BCBS |
| SJL | BCBS of Illinois |
| SJM | No prefix Assigned |
| SJN | Anthem BCBS of Georgia |
| SJO | Anthem Blue-Cross |
| SJP | BCBS of Illinois |
| SJQ | No prefix Assigned |
| SJR | Carefirst BCBS |
| SJS | BCBS of South Carolina |
| SJT | BCBS of Alabama |
| SJU | BCBS of Massachusetts |
| SJV | No prefix Assigned |
| SJW | No prefix Assigned |
| SJX | BCBS of South Carolina |
| SJY | Blue-Shield of California |
| SJZ | Highmark BCBS of Pennsylvania |
| SKA | BCBS of Minnesota |
| SKB | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| SKC | No prefix Assigned |
| SKD | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| SKE | No prefix Assigned |
| SKF | Anthem BCBS of Wisconsin |
| SKG | Anthem BCBS of Georgia |
| SKH | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| SKI | Anthem BCBS of Georgia |
| SKJ | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| SKK | BCBS of Illinois |
| SKL | BCBS of Illinois |
| SKM | No prefix Assigned |
| SKN | BCBS of Texas |
| SKO | Premera BCBS of Alaska |
| SKP | BCBS of Minnesota |
| SKQ | Anthem BCBS of Ohio |
| SKR | No prefix Assigned |
| SKS | BCBS of Illinois |
| SKT | BCBS of Nebraska |
| SKU | BCBS of North Carolina |
| SKV | No prefix Assigned |
| SKW | Anthem BCBS of Georgia |
| SKX | BCBS of Texas |
| SKY | BCBS of Illinois |
| SKZ | No prefix Assigned |
| SLA | BCBS of South Carolina |
| SLB | BCBS of Kansas City |
| SLC | BCBS of Louisiana |
| SLD | No prefix Assigned |
| SLE | Anthem BCBS of Colorado |
| SLF | Highmark BCBS of Pennsylvania |
| SLG | Anthem Blue-Cross |
| SLH | Premera BCBS of Alaska |
| SLI | BCBS of Alabama |
| SLJ | No prefix Assigned |
| SLK | BCBS of Minnesota |
| SLL | Highmark BCBS of Delaware |
| SLM | BCBS of Louisiana |
| SLN | BCBS of Minnesota |
| SLO | No prefix Assigned |
| SLP | No prefix Assigned |
| SLQ | No prefix Assigned |
| SLR | BCBS of Texas |
| SLS | Florida-Blue |
| SLT | BCBS of Massachusetts |
| SLU | Capital Blue-Cross of Pennsylvania |
| SLV | No prefix Assigned |
| SLW | BCBS of Western New York |
| SLX | Capital Blue-Cross of Pennsylvania |
| SLY | No prefix Assigned |
| SLZ | No prefix Assigned |
| SMA | BCBS of Nebraska |
| SMB | Anthem BCBS of Ohio |
| SMC | BCBS of Minnesota |
| SMD | Anthem BCBS of Indiana |
| SME | Empire BCBS of New York |
| SMF | Anthem BCBS of Virginia |
| SMG | Wellmark BCBS |
| SMH | BCBS of Alabama |
| SMI | No prefix Assigned |
| SMJ | Horizon BCBS of New Jersey |
| SMK | BCBS of Michigan |
| SML | BCBS of Illinois |
| SMM | Anthem BCBS of Ohio |
| SMN | Empire BCBS of New York |
| SMO | No prefix Assigned |
| SMP | Anthem BCBS of Ohio |
| SMQ | No prefix Assigned |
| SMR | No prefix Assigned |
| SMS | Wellmark BCBS |
| SMT | Anthem BCBS of Virginia |
| SMU | BCBS of Michigan |
| SMV | BCBS of Michigan |
| SMW | BCBS of Illinois |
| SMX | BCBS of Michigan |
| SMY | BCBS of Alabama |
| SMZ | BCBS of South Carolina |
| SNA | Anthem Blue-Cross |
| SNB | BCBS of Texas |
| SNC | No prefix Assigned |
| SND | No prefix Assigned |
| SNE | BCBS of Minnesota |
| SNF | No prefix Assigned |
| SNG | No prefix Assigned |
| SNH | No prefix Assigned |
| SNI | No prefix Assigned |
| SNJ | Horizon BCBS of New Jersey |
| SNK | BCBS of Arizona |
| SNL | BCBS of Illinois |
| SNM | No prefix Assigned |
| SNN | No prefix Assigned |
| SNO | BCBS of South Carolina |
| SNP | BCBS of Minnesota |
| SNQ | BCBS of Rhode Island |
| SNR | No prefix Assigned |
| SNS | BCBS of Illinois |
| SNT | No prefix Assigned |
| SNU | Anthem BCBS of Missouri |
| SNV | BCBS of Michigan |
| SNW | No prefix Assigned |
| SNX | Anthem Blue-Cross |
| SNY | Credence BCBS |
| SNZ | BCBS of Minnesota |
| SOA | Regence BCBS |
| SOB | BCBS of Michigan |
| SOC | Blue-Shield of California |
| SOD | Highmark BCBS of Delaware |
| SOE | BCBS of Illinois |
| SOF | Anthem BCBS of Ohio |
| SOG | No prefix Assigned |
| SOH | No prefix Assigned |
| SOI | No prefix Assigned |
| SOJ | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| SOK | Blue-Shield of California |
| SOL | BCBS of North Carolina |
| SOM | No prefix Assigned |
| SON | Blue-Shield of California |
| SOO | Blue-Shield of California |
| SOP | BCBS of Massachusetts |
| SOQ | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| SOR | Anthem BCBS of Kentucky |
| SOS | Florida-Blue |
| SOT | No prefix Assigned |
| SOU | Anthem BCBS of Missouri |
| SOV | No prefix Assigned |
| SOW | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| SOX | BCBS of Nebraska |
| SOY | No prefix Assigned |
| SOZ | No prefix Assigned |
| SPA | Anthem BCBS of Georgia |
| SPB | BCBS of Tennessee |
| SPC | No prefix Assigned |
| SPD | Anthem BCBS of Ohio |
| SPE | BCBS of Kansas City |
| SPF | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| SPG | Blue-Shield of California |
| SPH | BCBS of Arizona |
| SPI | Anthem Blue-Cross |
| SPJ | BCBS of South Carolina |
| SPK | Anthem BCBS of Virginia |
| SPL | BCBS of Illinois |
| SPM | No prefix Assigned |
| SPN | BCBS of Texas |
| SPO | BCBS of Western New York |
| SPP | No prefix Assigned |
| SPQ | BCBS of Illinois |
| SPR | Anthem BCBS of Virginia |
| SPS | BCBS of Massachusetts |
| SPT | BCBS of Minnesota |
| SPU | Carefirst BCBS |
| SPV | No prefix Assigned |
| SPW | Blue-Shield of California |
| SPX | Blue-Cross of Idaho |
| SPY | No prefix Assigned |
| SPZ | No prefix Assigned |
| SQA | No prefix Assigned |
| SQB | No prefix Assigned |
| SQC | Anthem BCBS of Ohio |
| SQD | Anthem BCBS of Georgia |
| SQE | BCBS of Minnesota |
| SQF | No prefix Assigned |
| SQG | Anthem BCBS of Ohio |
| SQH | Anthem BCBS of Indiana |
| SQI | No prefix Assigned |
| SQJ | Anthem BCBS of Colorado |
| SQK | Anthem Blue-Cross |
| SQL | No prefix Assigned |
| SQM | Blue-Shield of California |
| SQN | Premera BCBS of Alaska |
| SQO | BCBS of Michigan |
| SQP | Regence BCBS |
| SQQ | Blue-Cross of Idaho |
| SQR | BCBS of Minnesota |
| SQS | Anthem BCBS of Georgia |
| SQT | Anthem BCBS of Virginia |
| SQU | BCBS of South Carolina |
| SQV | Anthem BCBS of Georgia |
| SQW | Horizon BCBS of New Jersey |
| SQX | Anthem BCBS of Ohio |
| SQY | BCBS of South Carolina |
| SQZ | Anthem BCBS of Ohio |
| SRA | Horizon BCBS of New Jersey |
| SRB | Anthem BCBS of Missouri |
| SRC | BCBS of South Carolina |
| SRD | Horizon BCBS of New Jersey |
| SRE | BCBS of Louisiana |
| SRF | BCBS of North Carolina |
| SRG | Blue-Shield of California |
| SRH | Capital Blue-Cross of Pennsylvania |
| SRI | Highmark BCBS of Pennsylvania |
| SRJ | Regence BCBS |
| SRK | Anthem BCBS of Ohio |
| SRL | BCBS of Western New York |
| SRM | Anthem BCBS of Missouri |
| SRN | Anthem BCBS of Georgia |
| SRO | Excellus BCBS of New York |
| SRP | BCBS of South Carolina |
| SRQ | Anthem Blue-Cross |
| SRR | Anthem BCBS of Georgia |
| SRS | BCBS of South Carolina |
| SRT | Anthem BCBS of Wisconsin |
| SRU | Premera BCBS of Alaska |
| SRV | Anthem BCBS of Missouri |
| SRW | BCBS of Massachusetts |
| SRX | Anthem BCBS of Georgia |
| SRY | BCBS of Illinois |
| SRZ | Anthem BCBS of Missouri |
| SSA | Carefirst BCBS |
| SSB | No prefix Assigned |
| SSC | BCBS of North Carolina |
| SSD | Blue-Shield of California |
| SSE | BCBS of Minnesota |
| SSF | Anthem BCBS of Missouri |
| SSG | Wellmark BCBS |
| SSH | No prefix Assigned |
| SSI | BCBS of Minnesota |
| SSJ | No prefix Assigned |
| SSK | Empire BCBS of New York |
| SSL | Blue-Shield of California |
| SSM | Anthem BCBS of Georgia |
| SSN | No prefix Assigned |
| SSO | Blue-Shield of California |
| SSP | No prefix Assigned |
| SSQ | Blue-Cross of Idaho |
| SSR | No prefix Assigned |
| SSS | Regence BCBS |
| SST | BCBS of Massachusetts |
| SSU | Anthem Blue-Cross |
| SSV | No prefix Assigned |
| SSW | No prefix Assigned |
| SSX | BCBS of Texas |
| SSY | Anthem Blue-Cross |
| SSZ | Premera BCBS of Alaska |
| STA | BCBS of Tennessee |
| STB | Anthem BCBS of Ohio |
| STC | BCBS of Alabama |
| STD | Capital Blue-Cross of Pennsylvania |
| STE | Wellmark BCBS |
| STF | Anthem BCBS of Indiana |
| STG | BCBS of Tennessee |
| STH | Anthem BCBS of Georgia |
| STI | BCBS of Texas |
| STJ | Premera Blue-Cross of Alaska |
| STK | BCBS of South Carolina |
| STL | BCBS of Tennessee |
| STM | Highmark BCBS of Pennsylvania |
| STN | Highmark BCBS of Pennsylvania |
| STO | No prefix Assigned |
| STP | BCBS of Texas |
| STQ | BCBS of Tennessee |
| STR | Anthem BCBS of Indiana |
| STS | Blue-Shield of California |
| STT | BCBS of Tennessee |
| STU | Wellmark BCBS |
| STV | BCBS of Tennessee |
| STW | Carefirst BCBS |
| STX | BCBS of Illinois |
| STY | Anthem BCBS of Indiana |
| STZ | Florida-Blue |
| SUA | BCBS of Minnesota |
| SUB | Horizon BCBS of New Jersey |
| SUC | Horizon BCBS of New Jersey |
| SUD | Excellus BCBS of New York |
| SUE | Capital Blue-Cross of Pennsylvania |
| SUF | Empire BCBS of New York |
| SUG | BCBS of Massachusetts |
| SUH | BCBS of North Carolina |
| SUI | Anthem BCBS of Ohio |
| SUJ | Anthem BCBS of Georgia |
| SUK | No prefix Assigned |
| SUL | Wellmark BCBS |
| SUM | BCBS of Alabama |
| SUN | BCBS of Illinois |
| SUO | No prefix Assigned |
| SUP | BCBS of Illinois |
| SUQ | No prefix Assigned |
| SUR | BCBS of Illinois |
| SUS | Excellus BCBS of New York |
| SUT | Anthem Blue-Cross |
| SUU | BCBS of South Carolina |
| SUV | BCBS of Alabama |
| SUW | BCBS of Western New York |
| SUX | Horizon BCBS of New Jersey |
| SUY | Horizon BCBS of New Jersey |
| SUZ | Horizon BCBS of New Jersey |
| SVA | No prefix Assigned |
| SVB | BCBS of Michigan |
| SVC | Premera BCBS of Alaska |
| SVD | BCBS of Kansas City |
| SVE | BCBS of Tennessee |
| SVF | Capital Blue-Cross of Pennsylvania |
| SVG | BCBS of Kansas City |
| SVH | BCBS of Minnesota |
| SVI | No prefix Assigned |
| SVJ | No prefix Assigned |
| SVK | BCBS of Mississippi |
| SVL | BCBS of Kansas |
| SVM | No prefix Assigned |
| SVN | BCBS of North Carolina |
| SVO | Blue-Shield of California |
| SVP | Carefirst BCBS |
| SVQ | BCBS of Oklahoma |
| SVR | Anthem BCBS of Georgia |
| SVS | Anthem BCBS of Georgia |
| SVT | BCBS of Minnesota |
| SVU | BCBS of Illinois |
| SVV | No prefix Assigned |
| SVW | No prefix Assigned |
| SVX | Blue-Shield of California |
| SVY | BCBS of Minnesota |
| SVZ | No prefix Assigned |
| SWA | No prefix Assigned |
| SWB | BCBS of Arizona |
| SWC | No prefix Assigned |
| SWD | BCBS of Massachusetts |
| SWE | No prefix Assigned |
| SWF | No prefix Assigned |
| SWG | Anthem BCBS of Ohio |
| SWH | BCBS of Illinois |
| SWI | Anthem BCBS of Georgia |
| SWJ | BCBS of Illinois |
| SWK | BCBS of Illinois |
| SWL | No prefix Assigned |
| SWM | No prefix Assigned |
| SWN | No prefix Assigned |
| SWO | No prefix Assigned |
| SWP | Anthem BCBS of Kentucky |
| SWQ | No prefix Assigned |
| SWR | Highmark BCBS of Pennsylvania |
| SWS | BCBS of Massachusetts |
| SWT | BCBS of Arizona |
| SWU | Anthem BCBS of Ohio |
| SWV | Anthem BCBS of Wisconsin |
| SWW | Wellmark BCBS |
| SWX | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| SWY | BCBS of Minnesota |
| SWZ | Highmark BCBS of Pennsylvania |
| SXA | Arkansas BCBS |
| SXB | Wellmark BCBS |
| SXC | Anthem BCBS of Ohio |
| SXD | Blue-Shield of California |
| SXE | Anthem BCBS of Ohio |
| SXF | No prefix Assigned |
| SXG | No prefix Assigned |
| SXH | No prefix Assigned |
| SXI | Anthem BCBS of Ohio |
| SXJ | Anthem Blue-Cross |
| SXK | Empire BCBS of New York |
| SXL | No prefix Assigned |
| SXM | Blue-Shield of California |
| SXN | Regence BCBS |
| SXO | BCBS of Michigan |
| SXP | No prefix Assigned |
| SXQ | Anthem BCBS of Ohio |
| SXR | No prefix Assigned |
| SXS | No prefix Assigned |
| SXT | Carefirst BCBS |
| SXU | No prefix Assigned |
| SXV | Blue-Cross of Idaho |
| SXW | BCBS of Illinois |
| SXX | BCBS of Illinois |
| SXY | BCBS of Massachusetts |
| SXZ | Anthem Blue-Cross |
| SYA | Anthem BCBS of Ohio |
| SYB | BCBS of Illinois |
| SYC | Anthem BCBS of Ohio |
| SYD | BCBS of Arizona |
| SYE | BCBS of South Carolina |
| SYF | BCBS of Alabama |
| SYG | BCBS of Minnesota |
| SYH | BCBS of Minnesota |
| SYI | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| SYJ | Wellmark BCBS |
| SYK | Regence BCBS |
| SYL | No prefix Assigned |
| SYM | Carefirst BCBS |
| SYN | No prefix Assigned |
| SYO | BCBS of Michigan |
| SYP | Anthem BCBS of Georgia |
| SYQ | BCBS of Michigan |
| SYR | Highmark BCBS of Pennsylvania |
| SYS | Anthem BCBS of Wisconsin |
| SYT | BCBS of Tennessee |
| SYU | BCBS of Massachusetts |
| SYV | No prefix Assigned |
| SYW | No prefix Assigned |
| SYX | BCBS of Alabama |
| SYY | BCBS of Illinois |
| SYZ | Premera BCBS of Alaska |
| SZA | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| SZB | Regence BCBS |
| SZC | BCBS of Illinois |
| SZD | BCBS of Massachusetts |
| SZE | BCBS of Illinois |
| SZF | BCBS of Illinois |
| SZG | No prefix Assigned |
| SZH | Anthem BCBS of Virginia |
| SZI | Anthem BCBS of Georgia |
| SZJ | Highmark BCBS of Delaware |
| SZK | Wellmark BCBS |
| SZL | Carefirst BCBS |
| SZM | Highmark BCBS of Pennsylvania |
| SZN | BCBS of Nebraska |
| SZO | Blue-Shield of Northeastern New York |
| SZP | No prefix Assigned |
| SZQ | Anthem BCBS of Ohio |
| SZR | Premera BCBS of Alaska |
| SZS | Anthem BCBS of Ohio |
| SZT | No prefix Assigned |
| SZU | Anthem BCBS of Ohio |
| SZV | No prefix Assigned |
| SZW | No prefix Assigned |
| SZX | Premera BCBS of Alaska |
| SZY | Anthem Blue-Cross |
| SZZ | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| S2A | BCBS of Western New York |
| S2C | BCBS of Illinois |
| S2D | BCBS of Texas |
| S2E | BCBS of Illinois |
| S2F | BCBS of Illinois |
| S2G | BCBS of Texas |
| S2H | BCBS of Alabama |
| S2I | Anthem BCBS of Wisconsin |
| S2K | BCBS of Texas |
| S2L | BCBS of Illinois |
| S2M | Regence BCBS of Oregon |
| S2P | BCBS of Illinois |
| S2Q | BCBS of Massachusetts |
| S2R | BCBS of Illinois |
| S2S | Independence Blue Cross FOC |
| S2T | BCBS of Illinois |
| S2V | BCBS of Illinois |
| S2X | BCBS of Texas |
| S2Y | BCBS of Illinois |
| S2Z | BCBS of Texas |
| S3A | Blue Shield of Northeastern New York |
| S3B | Premera Blue Cross |
| S3C | Independence Blue Cross FOC |
| S3D | BCBS of Illinois |
| S3E | BCBS of Illinois |
| S3F | BCBS of Illinois |
| S3G | Premera Blue Cross |
| S3H | BCBS of Texas |
| S3K | BCBS of Texas |
| S3L | BCBS of Illinois |
| S3M | BCBS of Illinois |
| S3P | BCBS of Illinois |
| S3Q | Anthem Blue Cross of California |
| S3R | Highmark BCBS of Pennsylvania |
| S3S | Independence Blue Cross FOC |
| S3T | BCBS of Western New York |
| S3U | Highmark BCBS of Pennsylvania |
| S3Y | BCBS of Massachusetts |
| S4A | Premera Blue Cross |
| S4B | Premera Blue Cross |
| S4C | Premera Blue Cross |
| S4E | Premera Blue Cross |
| S4F | BCBS of Illinois |
| S4G | BCBS of Massachusetts |
| S4H | Anthem BCBS of Missouri |
| S4K | Independence Blue Cross FOC |
| S4L | BCBS of Illinois |
| S4M | BCBS of Illinois |
| S4N | BCBS of Illinois |
| S4P | BCBS of Illinois |
| S4R | Empire Blue Cross Blue Shield |
| S4U | BCBS of Texas |
| S4V | Premera Blue Cross |
| S4W | Regence BCBS of Oregon |
| S5A | BCBS of Texas |
| S5C | BCBS of Massachusetts |
| S5E | BCBS of Texas |
| S5G | Anthem BCBS of Indiana |
| S5H | Anthem BCBS of Missouri |
| S5L | BCBS of Illinois |
| S5M | BCBS of Illinois |
| S5P | BCBS of Minnesota |
| S5T | BCBS of Illinois |
| S5U | BCBS of Texas |
| S5V | Capital BlueCross |
| S6A | BCBS of Texas |
| S6B | BCBS of Illinois |
| S6E | BCBS of Texas |
| S6H | BCBS of Minnesota |
| S6K | Anthem BCBS of Ohio |
| S6L | BCBS of Texas |
| S6M | Anthem BCBS of Kentucky |
| S6P | Regence Blue Shield of Washington |
| S6Q | Empire Blue Cross Blue Shield |
| S6U | BCBS of Texas |
| S6W | Regence BCBS of Oregon |
| S6Y | BCBS of Illinois |
| S7A | Anthem BCBS of Missouri |
| S7B | Anthem BCBS of Missouri |
| S7C | Anthem BCBS of Missouri |
| S7E | Regence Blue Shield of Washington |
| S7G | Anthem BCBS of Virginia |
| S7L | Regence BCBS of Oregon |
| S7T | BCBS of Illinois |
| S7U | BCBS of Texas |
| S8A | Anthem BCBS of Ohio |
| S8C | Empire Blue Cross Blue Shield |
| S8K | Premera Blue Cross |
| S8L | BCBS of Illinois |
| S8N | BCBS of Minnesota |
| S8T | Anthem BCBS of Missouri |
| S8Y | Highmark BCBS of Pennsylvania |
| S9B | Premera Blue Cross |
| S9C | BCBS of Texas |
| S9H | Regence Blue Shield of Washington |
| S9J | No Prefix Assigned |
| S9L | Regence BCBS of Oregon |
| S9M | BCBS of Michigan |
| S9R | Anthem BCBS of Ohio |
| S9S | Independence Blue Cross FOC |
| S9T | Anthem BCBS of Kentucky |
