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
— 586-498 6XXX which blocks → MICHIGAN BELL TEL CO 9323 ROSEVILLE MI
— 586-501 2XXX3XXX5XXX6XXX8XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 CENTERLINE MI
— 586-504 2XXX3XXX6XXX7XXX8XXX · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 WARREN MI
— 586-506 3XXX4XXX6XXX9XXX which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 WARREN MI
— 586-507 not yet reported which blocks → AMERICAN MESSAGING SERVICES, LLC 9748 WARREN MI
— 586-510 0XXX4XXX5XXX6XXX8XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 CENTERLINE MI
— 586-511 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX MI
— 586-517 not yet reported which blocks → MI
— 586-529 not yet reported which blocks → SPOK, INC. 6630 WARREN MI
— 586-530 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 MT CLEMENS MI
— 586-531 none assigned yet which blocks → OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 2964 ROMEO MI
— 586-532 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 UTICA MI
— 586-536 1XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 WARREN MI
— 586-540 0XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 ROMEO MI
— 586-541 8XXX which blocks → PAETEC ITEL, LLC 829J ROSEVILLE MI
— 586-552 0XXX3XXX5XXX6XXX7XXX9XXX · 2 holders which blocks → MICHIGAN BELL TEL CO 9323 ROSEVILLE MI
— 586-553 1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 WARREN MI
— 586-554 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 WARREN MI
— 586-555 not yet reported which blocks → MULTIPLE OCN LISTING MULT DIR ASST MI
— 586-556 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 WARREN MI
— 586-558 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 CENTERLINE MI
— 586-563 0XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → MICHIGAN BELL TEL CO 9323 ROSEVILLE MI
— 586-565 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 WARREN MI
— 586-566 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 UTICA MI
— 586-567 3XXX which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 WARREN MI
— 586-568 not yet reported which blocks → AMERICAN MESSAGING SERVICES, LLC 9748 WARREN MI
— 586-569 1XXX3XXX4XXX5XXX6XXX8XXX9XXX · 3 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MI 7279 MT CLEMENS MI
— 586-573 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 CENTERLINE MI
— 586-574 5XXX6XXX7XXX8XXX · 3 holders which blocks → MICHIGAN BELL TEL CO 9323 CENTERLINE MI
— 586-575 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 CENTERLINE MI
— 586-576 1XXX2XXX6XXX7XXX9XXX · 4 holders which blocks → MICHIGAN BELL TEL CO 9323 CENTERLINE MI
— 586-578 9XXX which blocks → MICHIGAN BELL TEL CO 9323 CENTERLINE MI
— 586-580 0–9 XXXall 10 · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MI 770E UTICA MI
— 586-582 2XXX5XXX which blocks → MICHIGAN BELL TEL CO 9323 CENTERLINE MI
— 586-585 1XXX6XXX8XXX9XXX · 3 holders which blocks → PAETEC ITEL, LLC 829J ROSEVILLE MI
— 586-586 not yet reported which blocks → MI
— 586-589 not yet reported which blocks → TELNET WORLDWIDE, INC. 817J ROMEO MI
— 586-596 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 ROSEVILLE MI
— 586-598 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 MT CLEMENS MI
— 586-601 2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MI 7279 ROSEVILLE MI
— 586-607 not yet reported which blocks → SPOK, INC. 6630 WARREN MI
— 586-609 not yet reported which blocks → SPOK, INC. 6630 WARREN MI
— 586-611 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX MI
— 586-612 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 MT CLEMENS MI
— 586-615 none assigned yet which blocks → OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 2964 MT CLEMENS MI
— 586-616 not yet reported which blocks → MI
— 586-619 1XXX3XXX4XXX7XXX8XXX9XXX · 4 holders which blocks → PAETEC ITEL, LLC 829J CENTERLINE MI
— 586-620 not yet reported which blocks → TELNET WORLDWIDE, INC. 817J WARREN MI
— 586-625 0–9 XXXall 10 · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 ARMADA MI
— 586-627 4XXX which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MI 7279 MT CLEMENS 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.