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 251
LEVEL 3 COMMUNICATIONS, LLC - AL 17
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
2021-08-04 251-361 0–9 XXXall 10 · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AL 5255 MOBILE AL
2020-06-03 251-326 0–9 XXXwhole prefix which blocks → LEVEL 3 COMMUNICATIONS, LLC - AL 5255 MOBILE AL
2008-05-05 251-317 0–9 XXXall 10 · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AL 5255 CITRONELLE AL
2006-01-30 251-272 0–9 XXXall 10 · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AL 5255 MOBILE AL
2005-03-22 251-732 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AL 5255 FLOMATON AL
2005-03-02 251-616 0–9 XXXall 10 · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AL 5255 CLEAR SPG AL
2004-05-25 251-216 1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AL 5255 EVERGREEN AL
2004-01-27 251-252 0–9 XXXall 10 · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AL 5255 MOBILE AL
2003-10-27 251-217 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AL 5255 MOBILE AL
2002-08-27 251-202 0–9 XXXall 10 · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AL 5255 BAYMINETTE AL
2002-08-19 251-241 2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AL 5255 BREWTON AL
2002-05-13 251-545 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AL 5255 MOBILE AL
2002-04-29 251-418 1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AL 5255 MCINTOSH AL
2002-04-29 251-517 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AL 5255 FAIRHOPE AL
— 251-494 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AL 5255 BAYMINETTE AL
— 251-650 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AL 5255 MOBILE AL
— 251-744 0XXX1XXX2XXX4XXX5XXX6XXX7XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AL 5255 JACKSON AL

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.