NumberResearch Membership · Data 09/20/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/20/2026

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 313
MICHIGAN BELL TEL CO 244
OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 141
NEW CINGULAR WIRELESS PCS, LLC - IL 95
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 54
BANDWIDTH.COM CLEC, LLC - MI 28
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
2022-03-10 313-900 0–9 XXXall 10 · 3 holders which blocks → FRACTEL, LLC 965H DETROITZN5 MI
2022-03-08 313-654 0–9 XXXall 10 · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 DETROITZN5 MI
2022-02-28 313-726 0–9 XXXall 10 · 4 holders which blocks → TON80 COMMUNICATIONS, LLC 516J DETROITZN6 MI
2022-02-22 313-661 0–9 XXXall 10 · 3 holders which blocks → OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 2964 DETROITZN3 MI
2022-02-18 313-746 0–9 XXXall 10 · 4 holders which blocks → TON80 COMMUNICATIONS, LLC 516J DETROITZN1 MI
2022-01-25 313-669 0–9 XXXall 10 · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 DETROITZN5 MI
2022-01-10 313-200 0–9 XXXall 10 · 2 holders which blocks → OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 2964 DETROITZN1 MI
2021-11-24 313-504 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLCV - MI 543C DETROITZN3 MI
2021-11-18 313-490 0–9 XXXall 10 · 5 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MI 770E DETROITZN6 MI
2021-11-05 313-360 0–9 XXXall 10 · 2 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MI 770E DETROITZN1 MI
2021-11-03 313-612 0–9 XXXall 10 · 2 holders which blocks → ONVOY, LLCV - MI 543C DETROITZN1 MI
2021-10-19 313-540 0–9 XXXall 10 · 5 holders which blocks → VONAGE AMERICA LLC 197D DETROITZN4 MI
2021-07-29 313-650 0–9 XXXall 10 · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 DETROITZN6 MI
2021-07-07 313-572 0–9 XXXall 10 · 2 holders which blocks → ONVOY, LLCV - MI 543C DETROITZN1 MI
2021-06-16 313-514 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLCV - MI 543C DETROITZN4 MI
2021-06-02 313-547 0–9 XXXall 10 · 3 holders which blocks → HD CARRIER LLC 321J DETROITZN5 MI
2021-04-14 313-644 0–9 XXXall 10 · 5 holders which blocks → BANDWIDTH.COM CLEC, LLC - MI 991E DETROITZN3 MI
2021-04-12 313-542 0–9 XXXall 10 · 5 holders which blocks → BANDWIDTH.COM CLEC, LLC - MI 991E DETROITZN5 MI
2021-04-12 313-569 0–9 XXXall 10 · 2 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 DETROITZN5 MI
2021-04-02 313-944 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → FRACTEL, LLC 965H DETROITZN2 MI
2021-02-16 313-536 0–9 XXXall 10 · 3 holders which blocks → BANDWIDTH.COM CLEC, LLC - MI 991E DETROITZN4 MI
2021-02-12 313-548 0–9 XXXall 10 · 6 holders which blocks → BANDWIDTH.COM CLEC, LLC - MI 991E DETROITZN2 MI
2021-01-28 313-476 0–9 XXXall 10 · 5 holders which blocks → IP HORIZON LLC 515J DETROITZN6 MI
2021-01-12 313-489 0–9 XXXall 10 · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - MI 991E DETROITZN5 MI
2021-01-12 313-597 0–9 XXXall 10 · 3 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 DETROITZN5 MI
2021-01-11 313-380 0–9 XXXall 10 · 5 holders which blocks → BANDWIDTH.COM CLEC, LLC - MI 991E DETROITZN6 MI
2020-12-08 313-480 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 DETROITZN5 MI
2020-11-17 313-756 0–9 XXXall 10 · 5 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MI 770E DETROITZN1 MI
2020-10-14 313-591 0–9 XXXall 10 · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - MI 991E DETROITZN3 MI
2020-09-30 313-552 0–9 XXXall 10 · 4 holders which blocks → HD CARRIER LLC 321J DETROITZN1 MI
2020-09-08 313-998 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLCV - MI 543C DETROITZN1 MI
2020-09-02 313-479 0–9 XXXall 10 · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 DETROITZN6 MI
2020-09-02 313-513 0–9 XXXwhole prefix which blocks → ONVOY, LLCV - MI 543C DETROITZN1 MI
2020-09-02 313-631 0–9 XXXwhole prefix which blocks → ONVOY, LLCV - MI 543C DETROITZN2 MI
2020-09-02 313-634 0–9 XXXwhole prefix which blocks → ONVOY, LLCV - MI 543C DETROITZN3 MI
2020-09-02 313-763 0–9 XXXwhole prefix which blocks → ONVOY, LLCV - MI 543C DETROITZN5 MI
2020-08-19 313-512 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 DETROITZN4 MI
2020-08-17 313-678 0–9 XXXall 10 · 2 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MI 770E DETROITZN2 MI
2020-07-02 313-546 0–9 XXXall 10 · 3 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MI 770E DETROITZN1 MI
2020-06-04 313-955 0–9 XXXwhole prefix which blocks → METROPCS, INC. 5562 DETROITZN2 MI
2020-04-22 313-385 0–9 XXXall 10 · 4 holders which blocks → NUSO, LLC 478J DETROITZN1 MI
2019-12-19 313-946 0–9 XXXall 10 · 4 holders which blocks → FRACTEL, LLC 965H DETROITZN2 MI
2019-12-18 313-677 0–9 XXXall 10 · 2 holders which blocks → FRACTEL, LLC 965H DETROITZN4 MI
2019-12-18 313-688 0–9 XXXall 10 · 2 holders which blocks → FRACTEL, LLC 965H DETROITZN5 MI
2019-09-16 313-464 0–9 XXXall 10 · 5 holders which blocks → EXIANT COMMUNICATIONS LLC 114J DETROITZN6 MI
2019-09-10 313-710 0–9 XXXall 10 · 6 holders which blocks → ONVOY SPECTRUM, LLC 624H DETROITZN1 MI
2019-06-17 313-880 0–9 XXXall 10 · 4 holders which blocks → VOIP INNOVATIONS, LLC 597F DETROITZN1 MI
2019-05-02 313-488 0–9 XXXall 10 · 4 holders which blocks → COMMIO, LLC 939H DETROITZN1 MI
2019-04-11 313-474 0–9 XXXall 10 · 3 holders which blocks → BANDWIDTH.COM CLEC, LLC - MI 991E DETROITZN4 MI
2019-04-11 313-889 0–9 XXXall 10 · 3 holders which blocks → BANDWIDTH.COM CLEC, LLC - MI 991E DETROITZN5 MI

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/20/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.