NumberResearch Membership · Data 09/21/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/21/2026

Full prefixes (NXX) Thousands-blocks (1,000-number pools)

The Code holder is who opened each NPA-NXX prefix — not necessarily who holds the numbers. A prefix is 10,000 numbers, but under pooling its ten 1,000-number blocks are handed out individually, often to different carriers; the code holder may hold only one block, or none. The Thousands-blocks column shows how the ten blocks are really split — click which blocks → to see who holds each 1,000-number block and its last-4-digit range. Assignments are initial assignments; the current serving carrier may differ due to portability.

Most active assignees, all time — NPA 312
ILLINOIS BELL TEL CO 334
NEW CINGULAR WIRELESS PCS, LLC - IL 82
T-MOBILE USA, INC. 64
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 54
SPOK, INC. 33
New assignments by month Sep 2026 Aug 2026 Jul 2026 Jun 2026 May 2026 Apr 2026 Mar 2026 Feb 2026 Jan 2026 Dec 2025 Nov 2025 Oct 2025
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Recent NPA-NXX prefix assignments
AssignedNPA-NXXThousands-blocks taken (last-4 opening)Code holderOCNRate centerState
2026-01-29 312-679 0–9 XXXall 10 · 4 holders which blocks → U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 671J CHICGOZN01 IL
2026-01-27 312-426 0–9 XXXall 10 · 2 holders which blocks → ONVOY, LLC 224C CHICGOZN01 IL
2025-09-02 312-452 0–9 XXXall 10 · 3 holders which blocks → ONVOY SPECTRUM, LLC 624H CHICGOZN01 IL
2025-07-21 312-449 0–9 XXXall 10 · 2 holders which blocks → WAVENATION, LLC 700J CHICGOZN01 IL
2024-02-20 312-708 0–9 XXXwhole prefix which blocks → ONVOY SPECTRUM, LLC 624H CHICGOZN01 IL
2023-05-22 312-748 0–9 XXXwhole prefix which blocks → ONVOY, LLC 224C CHICGOZN01 IL
2023-05-19 312-773 0–9 XXXwhole prefix which blocks → ONVOY SPECTRUM, LLC 624H CHICGOZN01 IL
2022-09-19 312-910 0–9 XXXwhole prefix which blocks → ONVOY, LLC 224C CHICGOZN01 IL
2022-04-29 312-680 0–9 XXXwhole prefix which blocks → ONVOY, LLC 224C CHICGOZN01 IL
2020-07-28 312-530 0–9 XXXall 10 · 5 holders which blocks → STRATUS NETWORKS 495J CHICGOZN01 IL
2020-05-14 312-682 0–9 XXXall 10 · 4 holders which blocks → NUSO, LLC 478J CHICGOZN01 IL
2020-01-08 312-820 0–9 XXXwhole prefix which blocks → ONVOY, LLC 224C CHICGOZN01 IL
2019-06-28 312-847 0–9 XXXwhole prefix which blocks → ONVOY, LLC 224C CHICGOZN01 IL
2019-05-28 312-668 0–9 XXXall 10 · 6 holders which blocks → CSC WIRELESS, LLC 425J CHICGOZN01 IL
2019-05-13 312-779 0–9 XXXall 10 · 5 holders which blocks → ONVOY, LLC 224C CHICGOZN01 IL
2019-01-30 312-776 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2019-01-24 312-598 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLC 224C CHICGOZN01 IL
2019-01-18 312-900 0–9 XXXall 10 · 4 holders which blocks → FRACTEL, LLC 965H CHICGOZN01 IL
2018-08-14 312-584 0–9 XXXall 10 · 2 holders which blocks → VOIP INNOVATIONS, LLC 597F CHICGOZN01 IL
2018-07-12 312-872 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - IL 6115 CHICGOZN01 IL
2018-05-25 312-761 0–9 XXXall 10 · 3 holders which blocks → TELENGY LLC 148J CHICGOZN01 IL
2018-05-22 312-500 0–9 XXXwhole prefix which blocks → ONVOY, LLC 224C CHICGOZN01 IL
2018-05-07 312-815 0–9 XXXall 10 · 2 holders which blocks → AIRESPRING, INC. 996H CHICGOZN01 IL
2018-01-19 312-312 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLC 224C CHICGOZN01 IL
2017-10-23 312-392 0–9 XXXall 10 · 5 holders which blocks → ONVOY, LLC 224C CHICGOZN01 IL
2017-10-20 312-736 0–9 XXXall 10 · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - IL 7136 CHICGOZN01 IL
2017-10-20 312-741 0–9 XXXall 10 · 4 holders which blocks → PAETEC ITEL, LLC 829J CHICGOZN01 IL
2017-10-19 312-639 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 CHICGOZN01 IL
2017-10-19 312-728 0–9 XXXall 10 · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 CHICGOZN01 IL
2017-10-02 312-200 0–9 XXXall 10 · 2 holders which blocks → METROPCS, INC. 5562 CHICGOZN01 IL
2017-07-31 312-581 0–9 XXXall 10 · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 CHICGOZN01 IL
2017-07-25 312-579 0–9 XXXall 10 · 5 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 CHICGOZN01 IL
2017-07-21 312-538 0–9 XXXall 10 · 2 holders which blocks → METROPCS, INC. 5562 CHICGOZN01 IL
2017-07-20 312-535 0–9 XXXall 10 · 2 holders which blocks → BANDWIDTH.COM CLEC, LLC - IL 984E CHICGOZN01 IL
2017-07-07 312-481 0–9 XXXall 10 · 3 holders which blocks → METROPCS, INC. 5562 CHICGOZN01 IL
2017-06-02 312-438 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 CHICGOZN01 IL
2017-04-28 312-319 0–9 XXXall 10 · 6 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 CHICGOZN01 IL
2017-01-16 312-270 0–9 XXXall 10 · 6 holders which blocks → METROPCS, INC. 5562 CHICGOZN01 IL
2016-11-28 312-439 0–9 XXXwhole prefix which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 CHICGOZN01 IL
2016-11-28 312-723 0–9 XXXwhole prefix which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 CHICGOZN01 IL
2016-11-21 312-599 0–9 XXXall 10 · 2 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 CHICGOZN01 IL
2016-10-20 312-764 0–9 XXXall 10 · 3 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - IL 7136 CHICGOZN01 IL
2016-10-17 312-766 0–9 XXXwhole prefix which blocks → PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E CHICGOZN01 IL
2016-10-04 312-597 0–9 XXXall 10 · 2 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 CHICGOZN01 IL
2016-09-13 312-684 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2016-09-13 312-687 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2016-08-12 312-414 0–9 XXXall 10 · 5 holders which blocks → VONAGE AMERICA LLC 197D CHICGOZN01 IL
2016-08-08 312-783 0–9 XXXwhole prefix which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 CHICGOZN01 IL
2016-07-26 312-796 0–9 XXXall 10 · 5 holders which blocks → PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E CHICGOZN01 IL
2016-06-20 312-824 0–9 XXXall 10 · 4 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 CHICGOZN01 IL

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/21/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.