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