NumberResearch Membership · Data 09/19/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/19/2026

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 513
CINCINNATI BELL 251
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - OH 125
T-MOBILE USA, INC. 79
NEW CINGULAR WIRELESS PCS, LLC - IL 55
LEVEL 3 COMMUNICATIONS, LLC - OH 39
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
— 513-325 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - OH 6025 CINCINNATI OH
— 513-326 not yet reported which blocks → CINCINNATI BELL 9348 CINCINNATI OH
— 513-327 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - OH 4863 WILLIAMSBG OH
— 513-328 not yet reported which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-330 5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 671J HAMILTON OH
— 513-332 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX which blocks → PAETEC ITEL, LLC 829J CINCINNATI OH
— 513-333 not yet reported which blocks → CINCINNATI BELL 9348 CINCINNATI OH
— 513-335 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - OH 6025 CINCINNATI OH
— 513-336 not yet reported which blocks → BRIGHTSPEED OF NORTHWEST OHIO, INC. 0661 MASON OH
— 513-337 0XXX5XXX which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - OH 7836 CINCINNATI OH
— 513-338 3XXX4XXX6XXX7XXX9XXX · 2 holders which blocks → LEVEL 3 TELECOM OF OHIO, LLC - OH 7460 CINCINNATI OH
— 513-339 not yet reported which blocks → BRIGHTSPEED OF NORTHWEST OHIO, INC. 0661 MASON OH
— 513-340 0–9 XXXall 10 · 4 holders which blocks → TWC IP ENABLED SERVICES, LLC 793K LTL MIAMI OH
— 513-342 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - OH 4863 BETHANY OH
— 513-343 not yet reported which blocks → SPOK, INC. 6630 CINCINNATI OH
— 513-345 0XXX which blocks → CINCINNATI BELL 9348 CINCINNATI OH
— 513-346 0XXX8XXX9XXX which blocks → CINCINNATI BELL 9348 CINCINNATI OH
— 513-347 not yet reported which blocks → CINCINNATI BELL 9348 CINCINNATI OH
— 513-348 1XXX2XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-349 0XXX2XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-350 not yet reported which blocks → SPOK, INC. 6630 CINCINNATI OH
— 513-351 not yet reported which blocks → CINCINNATI BELL 9348 CINCINNATI OH
— 513-352 not yet reported which blocks → CINCINNATI BELL 9348 CINCINNATI OH
— 513-353 6XXX7XXX8XXX · 2 holders which blocks → CINCINNATI BELL 9348 CINCINNATI OH
— 513-354 0XXX9XXX · 2 holders which blocks → LEVEL 3 TELECOM OF OHIO, LLC - OH 7460 CINCINNATI OH
— 513-355 not yet reported which blocks → AMERICAN MESSAGING SERVICES, LLC 9748 MIDDLETOWN OH
— 513-357 not yet reported which blocks → CINCINNATI BELL 9348 CINCINNATI OH
— 513-358 not yet reported which blocks → CINCINNATI BELL 9348 CINCINNATI OH
— 513-361 not yet reported which blocks → CINCINNATI BELL 9348 CINCINNATI OH
— 513-362 0XXX9XXX which blocks → CINCINNATI BELL 9348 CINCINNATI OH
— 513-364 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - OH 6025 CINCINNATI OH
— 513-365 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - OH 6025 CINCINNATI OH
— 513-366 not yet reported which blocks → CINCINNATI BELL 9348 CINCINNATI OH
— 513-367 not yet reported which blocks → CINCINNATI BELL 9348 HARRISON OH
— 513-368 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - OH 6025 CINCINNATI OH
— 513-369 not yet reported which blocks → CINCINNATI BELL 9348 CINCINNATI OH
— 513-371 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLC - OH 464C CINCINNATI OH
— 513-373 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX which blocks → LEVEL 3 COMMUNICATIONS, LLC - OH 4863 CINCINNATI OH
— 513-374 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 CINCINNATI OH
— 513-375 1XXX3XXX6XXX which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 CINCINNATI OH
— 513-376 4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 CINCINNATI OH
— 513-377 5XXX6XXX8XXX which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 CINCINNATI OH
— 513-378 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - OH 6025 CINCINNATI OH
— 513-379 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - OH 6025 CINCINNATI OH
— 513-381 not yet reported which blocks → CINCINNATI BELL 9348 CINCINNATI OH
— 513-382 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - OH 6025 CINCINNATI OH
— 513-383 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-385 not yet reported which blocks → CINCINNATI BELL 9348 CINCINNATI OH
— 513-387 9XXX which blocks → CINCINNATI BELL 9348 CINCINNATI OH
— 513-388 1XXX6XXX7XXX8XXX · 2 holders which blocks → CINCINNATI BELL 9348 CINCINNATI OH

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/19/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.