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 203
SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 338
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT 61
NEW CINGULAR WIRELESS PCS, LLC - DC 52
OMNIPOINT COMMUNICATIONS, INC. - CT 47
LEVEL 3 COMMUNICATIONS, LLC - CT 41
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
— 203-342 not yet reported which blocks → SPOK, INC. 6630 BRIDGEPORT CT
— 203-344 0XXX1XXX2XXX4XXX5XXX7XXX8XXX · 5 holders which blocks → CABLEVISION LIGHTPATH, INC. - CT 4950 OLDGRNWICH CT
— 203-345 none assigned yet which blocks → CABLEVISION LIGHTPATH, INC. - CT 4950 BRIDGEPORT CT
— 203-346 1XXX8XXX9XXX · 2 holders which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 WATERBURY CT
— 203-348 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 STAMFORD CT
— 203-349 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - CT 7143 WESTPORT CT
— 203-350 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - CT 7143 MADISON CT
— 203-351 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 STAMFORD CT
— 203-352 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 STAMFORD CT
— 203-353 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 STAMFORD CT
— 203-354 none assigned yet which blocks → CABLEVISION LIGHTPATH, INC. - CT 4950 NORWALK CT
— 203-355 not yet reported which blocks → CABLEVISION LIGHTPATH, INC. - CT 4950 STAMFORD CT
— 203-356 5XXX which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 STAMFORD CT
— 203-357 5XXX which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 STAMFORD CT
— 203-358 7XXX which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 STAMFORD CT
— 203-359 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 STAMFORD CT
— 203-362 5XXX which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-363 4XXX which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 STAMFORD CT
— 203-364 4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 NEWTOWN CT
— 203-365 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-366 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-367 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-368 none assigned yet which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-370 not yet reported which blocks → AMERICAN MESSAGING SERVICES, LLC 9748 NEW HAVEN CT
— 203-371 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-372 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-373 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-374 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-375 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-376 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT 6388 NEW HAVEN CT
— 203-377 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-378 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-379 1XXX2XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 MERIDEN CT
— 203-380 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-381 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-382 3XXX4XXX which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-383 0XXX2XXX3XXX9XXX · 3 holders which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-384 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-385 2XXX which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-386 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-387 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 NEW HAVEN CT
— 203-388 5XXX6XXX8XXX · 2 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT 7230 STAMFORD CT
— 203-389 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 NEW HAVEN CT
— 203-391 1XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT 7230 STAMFORD CT
— 203-392 1XXX4XXX · 2 holders which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 NEW HAVEN CT
— 203-393 5XXX6XXX8XXX which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 NEW HAVEN CT
— 203-394 none assigned yet which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-395 none assigned yet which blocks → METROPCS, INC. 5562 BRIDGEPORT CT
— 203-396 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-397 6XXX which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 NEW HAVEN CT

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.