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
— 203-398 not yet reported which blocks → SPOK, INC. 6630 NORWALK CT
— 203-399 2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT 7230 STAMFORD CT
— 203-401 1XXX8XXX9XXX · 3 holders which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 NEW HAVEN CT
— 203-402 2XXX8XXX9XXX · 3 holders which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 HUNTINGTON CT
— 203-403 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - CT 7143 RIDGEFIELD CT
— 203-404 2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CT 4800 NEW HAVEN CT
— 203-406 7XXX which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 STAMFORD CT
— 203-407 9XXX which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 NEW HAVEN CT
— 203-408 0–9 XXXall 10 · 5 holders which blocks → BANDWIDTH.COM CLEC, LLC - CT 199F REDDING CT
— 203-409 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - CT 7143 OLDGRNWICH CT
— 203-410 none assigned yet which blocks → OMNIPOINT COMMUNICATIONS, INC. - CT 6624 NEW HAVEN CT
— 203-411 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX CT
— 203-412 not yet reported which blocks → AMERICAN MESSAGING SERVICES, LLC 9748 NEW HAVEN CT
— 203-413 not yet reported which blocks → PAETEC ITEL, LLC 829J GREENWICH CT
— 203-414 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 BRIDGEPORT CT
— 203-416 1XXX5XXX6XXX8XXX · 2 holders which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-417 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 DANBURY CT
— 203-418 0XXX1XXX3XXX4XXX5XXX6XXX7XXX · 3 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - CT 7143 FAIRFIELD CT
— 203-419 5XXX6XXX7XXX8XXX · 3 holders which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 WATERBURY CT
— 203-420 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 MERIDEN CT
— 203-421 2XXX6XXX which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 MADISON CT
— 203-422 1XXX9XXX · 2 holders which blocks → VERIZON NEW YORK, INC. 9104 GREENWICH CT
— 203-423 0XXX1XXX2XXX3XXX5XXX8XXX9XXX · 5 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - CT 7143 WILTON CT
— 203-425 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 STAMFORD CT
— 203-426 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 NEWTOWN CT
— 203-427 0XXX1XXX3XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 MERIDEN CT
— 203-428 1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT 7230 STAMFORD CT
— 203-429 3XXX4XXX5XXX7XXX8XXX9XXX · 4 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT 7230 WESTPORT CT
— 203-430 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 NEW HAVEN CT
— 203-431 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 RIDGEFIELD CT
— 203-432 not yet reported which blocks → BANDWIDTH.COM CLEC, LLC - CT 199F NEW HAVEN CT
— 203-433 0–9 XXXall 10 · 6 holders which blocks → COMCAST IP PHONE, LLC 318J BRANFORD CT
— 203-434 not yet reported which blocks → OMNIPOINT COMMUNICATIONS, INC. - CT 6624 NORWALK CT
— 203-435 not yet reported which blocks → OMNIPOINT COMMUNICATIONS, INC. - CT 6624 NEW HAVEN CT
— 203-436 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 NEW HAVEN CT
— 203-437 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 WATERBURY CT
— 203-438 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 RIDGEFIELD CT
— 203-439 1XXX2XXX3XXX4XXX5XXX6XXX8XXX · 4 holders which blocks → COMCAST IP PHONE, LLC 318J CHESHIRE CT
— 203-440 5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → COMCAST IP PHONE, LLC 318J MERIDEN CT
— 203-441 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - CT 7143 WOLCOTT CT
— 203-442 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - CT 7143 NEW CANAAN CT
— 203-443 0–9 XXXall 10 · 5 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 MERIDEN CT
— 203-444 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 NEW HAVEN CT
— 203-445 3XXX4XXX6XXX · 3 holders which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 TRUMBULL CT
— 203-446 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - CT 7143 ANSONIDRBY CT
— 203-447 0XXX4XXX6XXX8XXX9XXX · 3 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - CT 7143 HUNTINGTON CT
— 203-448 0XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT 7230 DANBURY CT
— 203-449 none assigned yet which blocks → METROPCS, INC. 5562 BRIDGEPORT CT
— 203-451 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 WESTPORT CT
— 203-452 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 TRUMBULL 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.