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
Clear Download CSV ↓
Recent NPA-NXX prefix assignments
AssignedNPA-NXXThousands-blocks taken (last-4 opening)Code holderOCNRate centerState
— 203-453 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 GUILFORD CT
— 203-454 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 WESTPORT CT
— 203-455 1XXX4XXX6XXX7XXX8XXX · 3 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT 7230 BRIDGEPORT CT
— 203-457 3XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 GUILFORD CT
— 203-458 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 GUILFORD CT
— 203-459 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 TRUMBULL CT
— 203-460 0XXX1XXX2XXX4XXX6XXX7XXX8XXX · 4 holders which blocks → METROPCS, INC. 5562 DANBURY CT
— 203-461 2XXX3XXX which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 STAMFORD CT
— 203-462 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 STAMFORD CT
— 203-463 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - CT 7143 SEYMOUR CT
— 203-464 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT 6388 NEW HAVEN CT
— 203-465 2XXX3XXX5XXX6XXX8XXX9XXX · 3 holders which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 WATERBURY CT
— 203-466 8XXX9XXX · 2 holders which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 NEW HAVEN CT
— 203-467 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 NEW HAVEN CT
— 203-468 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 NEW HAVEN CT
— 203-469 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 NEW HAVEN CT
— 203-470 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT 6388 DANBURY CT
— 203-471 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 XXXXXXXXXX CT
— 203-472 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 XXXXXXXXXX CT
— 203-473 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 XXXXXXXXXX CT
— 203-474 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 XXXXXXXXXX CT
— 203-475 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX CT
— 203-476 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 XXXXXXXXXX CT
— 203-477 not yet reported which blocks → SPOK, INC. 6630 NEW HAVEN CT
— 203-478 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 XXXXXXXXXX CT
— 203-479 0XXX2XXX6XXX9XXX · 3 holders which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 NEW HAVEN CT
— 203-480 1XXX2XXX3XXX4XXX5XXX6XXX7XXX which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT 7230 FAIRFIELD CT
— 203-481 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRANFORD CT
— 203-483 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRANFORD CT
— 203-484 3XXX8XXX · 2 holders which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRANFORD CT
— 203-485 2XXX6XXX which blocks → CABLEVISION LIGHTPATH, INC. - CT 4950 GREENWICH CT
— 203-486 8XXX9XXX · 2 holders which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 WOODBURY CT
— 203-488 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRANFORD CT
— 203-490 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - CT 7143 NAUGATUCK CT
— 203-492 9XXX which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 NEW HAVEN CT
— 203-493 0–9 XXXall 10 · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CT 4800 GEORGETOWN CT
— 203-494 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT 6388 NEW HAVEN CT
— 203-495 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 NEW HAVEN CT
— 203-496 4XXX5XXX8XXX which blocks → METROPCS, INC. 5562 GREENWICH CT
— 203-497 3XXX which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 NEW HAVEN CT
— 203-498 not yet reported which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 NEW HAVEN CT
— 203-499 7XXX8XXX9XXX which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 NEW HAVEN CT
— 203-502 1XXX3XXX7XXX8XXX9XXX · 4 holders which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 BRIDGEPORT CT
— 203-503 1XXX4XXX7XXX8XXX which blocks → SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT 9147 NEW HAVEN CT
— 203-505 0–9 XXXall 10 · 2 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT 6388 NORWALK CT
— 203-506 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - DC 4036 NEW HAVEN CT
— 203-507 0XXX1XXX2XXX · 2 holders which blocks → OMNIPOINT COMMUNICATIONS, INC. - CT 6624 NEW HAVEN CT
— 203-509 none assigned yet which blocks → METROPCS, INC. 5562 WATERBURY CT
— 203-510 none assigned yet which blocks → METROPCS, INC. 5562 WATERBURY CT
— 203-511 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX 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.