| IAB IAF IAI IAN IAO IAQ IAX IAZ IBG IBN IBY ICB ICQ ICS ICU ICX ICZ IDC IDG IDH IDV IDW IEE IEG IEM IEN IEV IFG IFM IFS IGB IGM IGR IGS IGT IHA IHC IHG IHP IHU IHV IIB IIH IIO IIS IJC IJM IJO IJW IKG IKJ IKM IKN IKP IKW IKZ ILI ILM ILN ILQ ILR ILU IMD IML IMN IMO IMP INF INH INM INN INU INX INZ IOA IOH IOK IOV IOW IPC IPF IPI IPJ IPO IQA IQP IQZ IRD IRE IRF IRH IRL IRN IRV ISF ISG ISR ISV ISY ITG ITI ITJ ITL ITN ITV IUD IUJ IUN IUU IUX IUZ IVA IVD IVG IVL IVM IVO IVQ IWB IWM IXC IXD IXS IXT IXV IXZ IYA IYE IYF IYK IYM IYO IYS IYT IZC IZH IZN IZQ IZT IZZ | Alpha Prefix not assigned or unallocated |
| ICC IHX IMH IRC IYP | Anthem Blue Cross Blue Shield of Colorado |
| IET IRU IUB IUP IWR | Anthem Blue Cross Blue Shield of Connecticut |
| IBK IBS ICJ ICN ICP IFA IFE IHY IHZ IIF IJF IJG IJH IJI IJJ IJK IJL IJQ IJT IJV IJX IKU IPP IQB IQD IQK IQL IQM IQQ IQV IQW IQX ITT ITZ IUY IWI IWL IWQ IYL IZD IZV | Anthem Blue Cross Blue Shield of Georgia |
| IAD IEB IED INR IQG IVZ IWA IWJ IXF IXG IXH IXJ | Anthem Blue Cross Blue Shield of Indiana |
| IFR IJB IKA IKT IMS INA INJ IQH ISK IYH | Anthem Blue Cross Blue Shield of Kentucky |
| IMK | Anthem Blue Cross Blue Shield of Maine |
| IKR IMJ IMX IQI ISS IUF IWO IXP | Anthem Blue Cross Blue Shield of Missouri |
| IFP | Anthem Blue Cross Blue Shield of Nevada |
| IJD | Anthem Blue Cross Blue Shield of New Hampshire |
| ICR ICY IFX IHE IMW ING IOX IPQ IQT IRO IRR ISA IST ITP IUC IUT IUW IVX IWN IXE IXK IXN IXX IXY IZK | Anthem Blue Cross Blue Shield of Ohio |
| IAG ICH IDD IDJ IDQ IDT IER IKB IKC IKL IMC INT IPA IPG IQJ ISE IWC IWU | Anthem Blue Cross Blue Shield of Virginia |
| IAA IBC IBD IJA IJS ILJ ILO IQR ISP IVJ IVW IYB IZB | Anthem Blue Cross Blue Shield of Wisconsin |
| IBX IDR ILH ILL ILY INC INK INY IQO IRZ IVS | Anthem Bluecross of California |
| ITS IXA | Arkansas Blue Cross Blue Shield |
| IAR IBH IBU IGE IHH IHT ILF ILV ILX IMR IRK IZA | Blue Cross Blue Shield of Alabama |
| ISD IVR | Blue Cross Blue Shield of Arizona |
| IBA IBE IBT IBW IDX IEL IEW IIT ILT IPT ITW | Blue Cross Blue Shield of Illinois |
| IDO IPH | Blue Cross Blue Shield of Kansas |
| IDS ILP IPL IRM ISQ IVC IWV IYJ | Blue Cross Blue Shield of Kansas City |
| ICG IDU IEP IEU IGU IHO IHQ IMU IOU IQN IRG IUK IVI | Blue Cross Blue Shield of Louisiana |
| IAS IBV ICW IEF IHS IIN ILB IMB IMV IRB IRX ISO ITC IUH IUM IWW | Blue Cross Blue Shield of Massachusetts |
| IAE IBJ IBR ICV IEX IKK IKV IKX ILD ILZ IOD IOI IOJ IOL IOM IOO IOQ IPV IQU ITF ITM IVB IVP IWK IWP IWZ IXR IXW IYI IYU IYV IYX IYY IYZ IZG IZI IZJ IZL IZM IZO IZR IZS IZW IZX IZY | Blue Cross Blue Shield of Michigan |
| IVK | Blue Cross Blue Shield of Mississippi |
| IAU IHD IKY | Blue Cross Blue Shield of Nebraska |
| ICO IEO IND INP IOS ITE | Blue Cross Blue Shield of North Carolina |
| IPZ IRI IUI IVH IVY | Blue Cross Blue Shield of Rhode Island |
| IAY IDY IEJ IEY IFZ IIR IIY IJP IJZ IMY INE INV IOR IOY IQY IRJ IXQ IYQ | Blue Cross Blue Shield of South Carolina |
| III IMQ INL IOB IQE IQF IVF IVN | Blue Cross Blue Shield of Tennessee |
| IES IJU | Blue Cross Blue Shield of Texas |
| ICT IFC IGO IIP IJE IMM IOP IPY IWX | Blue Cross Blue Shield of Western New York |
| IDA IDE IDF IDL IDM IDN IDP IID IIX IJR IPU ISN ISU ISW ISZ IZP | Bluecross of Idaho |
| IAK IAM IBM ICM IDI IEC IGF IGG IHN IHR IHW IIA IIW IKS ILG ILW INO IOC IOF IOZ IPE IPK IPS IRW ISI IVE IXB IXL IXM IXO | Blueshield of California |
| IOG ITO | Blueshield of Northeastern New York |
| IJY IQC ITH IWT IYD | Capital Bluecross of Pennsylvania |
| IAJ ICA ICD ICE ICF ICK ICL IEK IEZ IFQ IFY IGC IGW IGX IGY ISH ITA ITK IUL IUQ IWD IWH IZE | Carefirst Blue Cross Blue Shield(Maryland/District of Columbia/Northern Virginia) |
| IAT IDK IEQ IHF IHJ ILA IOE ITR IUE IUO IWF IWY | Empire Blue Cross Blue Shield of New York |
| IMA IWG | Excellus Blue Cross Blue Shield of New York |
| ICI IDB IIQ IIV IIZ IJN IKI ION IRP IRQ IRS IVU IXI IYG IYR | Florida Blue |
| IHM IKO INI | Highmark Blue Cross Blue Shield of Delaware |
| IFH IFI IFJ IFK IFN IFO IFT IFU IFV IFW IGK IGL IGN IGQ IGV IGZ IHI IHK IIE IIG IIJ IIK IIL IIM IME IOT IPB IPD IPM IPN ISM IVV | Highmark Blue Cross Blue Shield of Pennsylvania |
| IHL | Highmark Blue Cross Blue Shield of West Virginia |
| IBB IIC IRA ISC | Horizon Blue Cross Blue Shield of New Jersey |
| IBL IBO IEI IGA IGH IGJ IIU IKE IKF INW IQS IRY ISJ ITD ITY IUR IUS IXU IYC IYW IZF | Independence Bluecross of Philadelphia and Southeastern Pennsylvania |
| IEH ILS ISB IUG | Premera Blue Cross Blue Shield of Alaska |
| INB IYN | Premera Bluecross of Alaska |
| IAC IBQ IBZ IEA IFD IFL ILK IMF IMG INQ IPW ITU ITX IUV | Regence Blue Cross Blue Shield(Oregon/Idaho/Utah/Washington) |
| IAH IAL IAP IAV IAW IBF IBI IBP IDZ IFB IFF IGD IGI IGP IHB IKD IKH IKQ ILC ILE IMI IMT IMZ INS IPR IPX IRT ISL ISX ITB ITQ IUA IVT IWE IWS IZU | Wellmark Blue Cross Blue Shield of South Dakota/Iowa |