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
LEVEL 3 COMMUNICATIONS, LLC - MI 26
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
2006-03-07 586-244 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 NEW HAVEN MI
2004-02-25 586-203 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 MT CLEMENS MI
2002-09-10 586-797 none assigned yet which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 UTICA MI
2002-08-28 586-648 0–9 XXXall 10 · 9 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 NEWBALTIMR MI
2002-03-28 586-623 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 ROMEO MI
2001-06-18 586-207 0XXX1XXX3XXX4XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 WASHINGTON MI
— 586-270 1XXX2XXX3XXX6XXX7XXX8XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 NEW HAVEN MI
— 586-273 2XXX3XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 NEWBALTIMR MI
— 586-435 4XXX9XXX · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 ROSEVILLE MI
— 586-477 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 MT CLEMENS MI
— 586-486 0–9 XXXall 10 · 7 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 CENTERLINE MI
— 586-501 2XXX3XXX5XXX6XXX8XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 CENTERLINE MI
— 586-510 0XXX4XXX5XXX6XXX8XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 CENTERLINE MI
— 586-540 0XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 ROMEO MI
— 586-625 0–9 XXXall 10 · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 ARMADA MI
— 586-649 0XXX2XXX3XXX6XXX7XXX8XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 MT CLEMENS MI
— 586-693 5XXX which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 WARREN MI
— 586-723 1XXX2XXX3XXX4XXX5XXX6XXX · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 MT CLEMENS MI
— 586-799 2XXX3XXX4XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 UTICA MI
— 586-838 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 WARREN MI
— 586-863 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 ROSEVILLE MI
— 586-894 2XXX3XXX5XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 ROMEO MI
— 586-928 0XXX1XXX2XXX3XXX4XXX5XXX7XXX8XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 NEW HAVEN MI
— 586-932 1XXX2XXX3XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 UTICA MI
— 586-933 0XXX1XXX3XXX5XXX6XXX7XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 WARREN MI
— 586-981 0XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - MI 6120 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.