NumberResearch Membership · Data 09/19/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/19/2026

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 231
NEW CINGULAR WIRELESS PCS, LLC - IL 72
MICHIGAN BELL TEL CO 72
FRONTIER NORTH, INC. - MI 52
ONVOY, LLCV - MI 49
TELNET WORLDWIDE, INC. 43
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
2026-03-19 231-469 0XXX1XXX4XXX9XXX · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 MUSKEGON MI
2025-07-31 231-552 2XXX9XXX · 2 holders which blocks → OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 2964 CHARLEVOIX MI
2025-05-22 231-341 0XXX9XXX · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 LAKE ANN MI
2025-03-12 231-214 1XXX which blocks → CHARTER IP ENABLED SERVICES, LLC 792K LAKE NORTH MI
2024-09-05 231-456 0XXX9XXX · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 GLEN LAKE MI
2024-03-01 231-453 1XXX which blocks → CHARTER IP ENABLED SERVICES, LLC 792K HOLTON MI
2023-07-14 231-428 0–9 XXXall 10 · 5 holders which blocks → ONVOY, LLCV - MI 543C MUSKEGON MI
2023-07-14 231-430 0XXX1XXX2XXX · 3 holders which blocks → ONVOY, LLCV - MI 543C BOYNE CITY MI
2023-07-14 231-435 2XXX which blocks → ONVOY, LLCV - MI 543C EASTPORT MI
2023-07-14 231-438 2XXX4XXX7XXX · 3 holders which blocks → ONVOY, LLCV - MI 543C HARBOR SPG MI
2023-07-14 231-446 2XXX5XXX · 2 holders which blocks → ONVOY, LLCV - MI 543C NORTHPORT MI
2023-07-14 231-451 2XXX which blocks → ONVOY, LLCV - MI 543C WILLIAMSBG MI
2023-07-11 231-210 0XXX2XXX6XXX · 3 holders which blocks → ONVOY, LLCV - MI 543C ST JAMES MI
2023-07-11 231-418 0XXX2XXX9XXX · 3 holders which blocks → ONVOY, LLCV - MI 543C MARION MI
2023-07-11 231-419 0XXX1XXX2XXX · 2 holders which blocks → ONVOY, LLCV - MI 543C BELLAIRE MI
2023-07-11 231-426 2XXX which blocks → ONVOY, LLCV - MI 543C RAVENNA MI
2023-01-06 231-417 0XXX1XXX6XXX · 3 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MI 770E PETOSKEY MI
2022-12-05 231-415 1XXX which blocks → CHARTER IP ENABLED SERVICES, LLC 792K DUBLIN MI
2022-08-12 231-410 0XXX1XXX2XXX4XXX7XXX8XXX9XXX · 6 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 MANISTEE MI
2022-03-10 231-391 0XXX7XXX8XXX9XXX · 3 holders which blocks → BANDWIDTH.COM CLEC, LLC - MI 991E WALLOON LK MI
2022-03-07 231-663 1XXX3XXX6XXX7XXX · 4 holders which blocks → TON80 COMMUNICATIONS, LLC 516J MESICK MI
2022-03-07 231-772 1XXX2XXX7XXX · 3 holders which blocks → TON80 COMMUNICATIONS, LLC 516J WELLSTON MI
2022-02-28 231-963 6XXX which blocks → TON80 COMMUNICATIONS, LLC 516J MCBAIN MI
2022-02-22 231-566 0XXX1XXX5XXX6XXX · 3 holders which blocks → TON80 COMMUNICATIONS, LLC 516J HARRIETTA MI
2022-02-22 231-699 0XXX1XXX9XXX · 2 holders which blocks → TON80 COMMUNICATIONS, LLC 516J FOUNTAIN MI
2022-02-22 231-966 6XXX which blocks → TON80 COMMUNICATIONS, LLC 516J FREESOIL MI
2022-02-18 231-746 0XXX2XXX3XXX4XXX5XXX7XXX9XXX · 3 holders which blocks → TON80 COMMUNICATIONS, LLC 516J CHEBOYGAN MI
2022-02-14 231-413 0XXX1XXX8XXX9XXX · 3 holders which blocks → OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 2964 KALKASKA MI
2022-02-04 231-405 0XXX5XXX which blocks → ONVOY, LLCV - MI 543C ALDEN MI
2022-02-04 231-406 0XXX1XXX5XXX · 2 holders which blocks → ONVOY, LLCV - MI 543C FALMOUTH MI
2022-02-04 231-407 0XXX7XXX which blocks → ONVOY, LLCV - MI 543C MECOSTA MI
2022-01-21 231-402 0–9 XXXall 10 · 2 holders which blocks → ONVOY, LLCV - MI 543C MUSKEGON MI
2022-01-10 231-380 0XXX1XXX3XXX7XXX8XXX9XXX · 4 holders which blocks → OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 2964 NEWAYGO MI
2021-12-21 231-401 0XXX1XXX2XXX3XXX7XXX8XXX9XXX · 3 holders which blocks → PENINSULA FIBER NETWORK, LLC - MI 116F TRAVERSECY MI
2021-11-03 231-397 0–9 XXXall 10 · 4 holders which blocks → OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 2964 MANISTEE MI
2021-10-29 231-396 0–9 XXXall 10 · 5 holders which blocks → ONVOY, LLCV - MI 543C CADILLAC MI
2021-10-26 231-390 0–9 XXXall 10 · 4 holders which blocks → OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 2964 BIG RAPIDS MI
2021-10-06 231-387 0–9 XXXall 10 · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 PETOSKEY MI
2021-09-23 231-454 0XXX2XXX3XXX4XXX9XXX · 2 holders which blocks → METROPCS, INC. 5562 TRAVERSECY MI
2021-09-22 231-550 1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → METROPCS, INC. 5562 PETOSKEY MI
2021-09-16 231-968 0XXX1XXX2XXX3XXX4XXX8XXX · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - MI 991E CADILLAC MI
2021-09-08 231-880 0–9 XXXall 10 · 5 holders which blocks → SKYE TELECOM LLC DBA SKYETEL 622J MUSKEGON MI
2021-09-03 231-320 0XXX1XXX2XXX4XXX5XXX8XXX9XXX · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - MI 991E TRCHRIVBDG MI
2021-09-03 231-370 0–9 XXXall 10 · 5 holders which blocks → OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 2964 MUSKEGON MI
2021-09-03 231-371 0XXX1XXX2XXX7XXX · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - MI 991E TUSTIN MI
2021-08-26 231-379 0XXX1XXX2XXX7XXX9XXX · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - MI 991E ONEKAMA MI
2021-07-20 231-385 0XXX1XXX2XXX3XXX5XXX6XXX7XXX9XXX · 4 holders which blocks → ONVOY, LLCV - MI 543C CORAL MI
2021-07-02 231-376 0XXX6XXX7XXX · 3 holders which blocks → ONVOY, LLCV - MI 543C TWIN LAKE MI
2021-07-02 231-393 1XXX3XXX · 2 holders which blocks → ONVOY SPECTRUM, LLC 624H LE ROY MI
2021-07-02 231-466 0XXX1XXX3XXX4XXX7XXX9XXX · 5 holders which blocks → ONVOY SPECTRUM, LLC 624H EVART MI

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/19/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.