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 586
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 132
MICHIGAN BELL TEL CO 100
NEW CINGULAR WIRELESS PCS, LLC - IL 60
OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 43
AMERICAN MESSAGING SERVICES, LLC 27
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
2016-11-15 586-551 0–9 XXXall 10 · 3 holders which blocks → OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 2964 MT CLEMENS MI
2016-11-08 586-305 0–9 XXXwhole prefix which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 MT CLEMENS MI
2016-09-22 586-696 0–9 XXXall 10 · 3 holders which blocks → METROPCS, INC. 5562 ROSEVILLE MI
2016-04-14 586-267 0–9 XXXall 10 · 5 holders which blocks → BANDWIDTH.COM CLEC, LLC - MI 991E MT CLEMENS MI
2016-03-31 586-251 0–9 XXXall 10 · 5 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 UTICA MI
2016-03-23 586-571 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLCV - MI 543C CENTERLINE MI
2016-03-15 586-250 0–9 XXXall 10 · 6 holders which blocks → ONVOY, LLCV - MI 543C WARREN MI
2016-03-14 586-371 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLCV - MI 543C WASHINGTON MI
2016-03-14 586-701 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLCV - MI 543C NEW HAVEN MI
2016-02-26 586-240 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 MT CLEMENS MI
2016-02-26 586-396 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 MT CLEMENS MI
2016-02-26 586-483 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 MT CLEMENS MI
2016-02-26 586-527 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 MT CLEMENS MI
2016-02-26 586-550 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 WARREN MI
2016-02-26 586-559 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 WARREN MI
2016-02-26 586-628 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 WARREN MI
2016-02-26 586-676 0–9 XXXall 10 · 3 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 MT CLEMENS MI
2016-02-26 586-695 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 MT CLEMENS MI
2016-02-26 586-922 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 WARREN MI
2016-02-10 586-377 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 WARREN MI
2016-02-10 586-449 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 WARREN MI
2016-01-28 586-297 0–9 XXXall 10 · 2 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MI 770E CENTERLINE MI
2016-01-21 586-842 0–9 XXXall 10 · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 MT CLEMENS MI
2016-01-14 586-448 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 MT CLEMENS MI
2016-01-14 586-629 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 MT CLEMENS MI
2016-01-14 586-848 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 MT CLEMENS MI
2016-01-04 586-241 0–9 XXXall 10 · 3 holders which blocks → METROPCS, INC. 5562 ROSEVILLE MI
2015-12-11 586-257 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLCV - MI 543C MT CLEMENS MI
2015-12-04 586-299 0–9 XXXall 10 · 2 holders which blocks → ONVOY, LLCV - MI 543C MT CLEMENS MI
2015-10-09 586-474 0–9 XXXall 10 · 3 holders which blocks → OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 2964 WARREN MI
2015-10-09 586-577 0–9 XXXall 10 · 2 holders which blocks → OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 2964 WARREN MI
2015-09-30 586-272 0–9 XXXall 10 · 3 holders which blocks → COMCAST IP PHONE, LLC 318J WARREN MI
2015-09-09 586-253 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 WARREN MI
2015-09-09 586-429 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 WARREN MI
2015-09-02 586-338 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 MT CLEMENS MI
2015-09-02 586-414 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 MT CLEMENS MI
2015-08-27 586-259 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 MT CLEMENS MI
2015-08-27 586-386 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 MT CLEMENS MI
2015-08-27 586-545 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 MT CLEMENS MI
2015-08-26 586-539 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 MT CLEMENS MI
2015-08-05 586-252 0–9 XXXall 10 · 4 holders which blocks → METROPCS, INC. 5562 ROSEVILLE MI
2015-07-24 586-999 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLCV - MI 543C WARREN MI
2015-07-23 586-333 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLCV - MI 543C MT CLEMENS MI
2015-07-16 586-357 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 MT CLEMENS MI
2015-07-16 586-375 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 MT CLEMENS MI
2015-07-16 586-641 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 WARREN MI
2015-07-16 586-748 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 WARREN MI
2015-07-16 586-828 0–9 XXXwhole prefix which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 MT CLEMENS MI
2015-06-29 586-237 0–9 XXXall 10 · 2 holders which blocks → OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 2964 WARREN MI
2015-06-29 586-733 0–9 XXXwhole prefix which blocks → OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 2964 WARREN 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.