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
— 231-497 0–9 XXXall 10 · 7 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 BOYNE CITY MI
— 231-499 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 TRAVERSECY MI
— 231-510 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 MANISTEE MI
— 231-511 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX MI
— 231-512 not yet reported which blocks → AMERICAN MESSAGING SERVICES, LLC 9748 TRAVERSECY MI
— 231-514 not yet reported which blocks → AMERICAN MESSAGING SERVICES, LLC 9748 CADILLAC MI
— 231-516 not yet reported which blocks → AMERICAN MESSAGING SERVICES, LLC 9748 PETOSKEY MI
— 231-517 not yet reported which blocks → MI
— 231-522 not yet reported which blocks → 123.NET, LLC 2550 LUTHER MI
— 231-525 0XXX1XXX2XXX3XXX4XXX5XXX7XXX · 4 holders which blocks → MICHIGAN BELL TEL CO 9323 WOLVERINE MI
— 231-526 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 HARBOR SPG MI
— 231-527 4XXX5XXX7XXX8XXX9XXX · 4 holders which blocks → MICHIGAN BELL TEL CO 9323 BIG RAPIDS MI
— 231-529 4XXX5XXX7XXX · 3 holders which blocks → BRIGHTSPEED OF MICHIGAN, LLC 0702 BRUTUS MI
— 231-533 0XXX1XXX2XXX · 2 holders which blocks → FRONTIER NORTH, INC. - MI 0695 BELLAIRE MI
— 231-535 0XXX1XXX4XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → MICHIGAN BELL TEL CO 9323 WALLOON LK MI
— 231-536 5XXX6XXX8XXX · 3 holders which blocks → MICHIGAN BELL TEL CO 9323 EASTJORDAN MI
— 231-537 not yet reported which blocks → BRIGHTSPEED OF MICHIGAN, LLC 0702 LEVERING MI
— 231-539 0XXX1XXX2XXX3XXX4XXX5XXX6XXX9XXX · 7 holders which blocks → MICHIGAN BELL TEL CO 9323 PELLSTON MI
— 231-544 0XXX1XXX7XXX · 3 holders which blocks → FRONTIER NORTH, INC. - MI 0695 CENTRAL LK MI
— 231-546 not yet reported which blocks → BRIGHTSPEED OF MICHIGAN, LLC 0702 ELMIRA MI
— 231-547 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 CHARLEVOIX MI
— 231-548 not yet reported which blocks → BRIGHTSPEED OF MICHIGAN, LLC 0702 ALANSON MI
— 231-549 8XXX which blocks → BRIGHTSPEED OF MICHIGAN, LLC 0702 BOYNEFALLS MI
— 231-555 not yet reported which blocks → MULTIPLE OCN LISTING MULT DIR ASST MI
— 231-557 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 MUSKEGON MI
— 231-563 0–9 XXXall 10 · 4 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 MUSKEGON MI
— 231-564 3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 KALKASKA MI
— 231-568 not yet reported which blocks → 123.NET, LLC 2550 TRAVERSECY MI
— 231-569 not yet reported which blocks → AMERICAN MESSAGING SERVICES, LLC 9748 PETOSKEY MI
— 231-571 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → FRONTIER NORTH, INC. - MI 0695 MUSKEGON MI
— 231-578 none assigned yet which blocks → OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 2964 MUSKEGON MI
— 231-582 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 BOYNE CITY MI
— 231-584 not yet reported which blocks → PIGEON TEL. CO. 0721 ALBA MI
— 231-585 not yet reported which blocks → PIGEON TEL. CO. 0721 LAKE NORTH MI
— 231-586 not yet reported which blocks → MI
— 231-587 3XXX6XXX7XXX · 3 holders which blocks → MICHIGAN BELL TEL CO 9323 MANCELONA MI
— 231-588 0XXX1XXX3XXX5XXX7XXX8XXX · 4 holders which blocks → FRONTIER NORTH, INC. - MI 0695 ELLSWORTH MI
— 231-590 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 TRAVERSECY MI
— 231-591 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 BIG RAPIDS MI
— 231-592 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 BIG RAPIDS MI
— 231-593 not yet reported which blocks → SPOK, INC. 6630 CADILLAC MI
— 231-594 0–9 XXXall 10 · 5 holders which blocks → TWILIO INTERNATIONAL, INC. 506J HART MI
— 231-596 not yet reported which blocks → SPOK, INC. 6630 HARBOR SPG MI
— 231-597 3XXX4XXX5XXX6XXX7XXX · 3 holders which blocks → MICHIGAN BELL TEL CO 9323 CHEBOYGAN MI
— 231-598 4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 BIG RAPIDS MI
— 231-599 0XXX1XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → FRONTIER NORTH, INC. - MI 0695 EASTPORT MI
— 231-604 not yet reported which blocks → SPOK, INC. 6630 KALKASKA MI
— 231-605 not yet reported which blocks → SPOK, INC. 6630 NEWAYGO MI
— 231-608 not yet reported which blocks → SPOK, INC. 6630 FRANKFORT MI
— 231-611 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX 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.