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 443
TELEPORT COMMUNICATIONS AMERICA, LLC - MD 48
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
2004-11-01 443-437 0–9 XXXall 10 · 8 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 POCOMOKE MD
2004-04-20 443-933 0–9 XXXall 10 · 5 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 COCKEYSVL MD
— 443-231 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 ESSEX MD
— 443-267 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 DARLINGTON MD
— 443-272 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 RANDALLSTN MD
— 443-273 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 7 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 REISTERSTN MD
— 443-297 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 ARBUTUS MD
— 443-343 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 MILLERSVL MD
— 443-348 0XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 WOODLAWN MD
— 443-360 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 ABERDEEN MD
— 443-364 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 ELLICOTTCY MD
— 443-376 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 DUNDALK MD
— 443-392 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 2 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 BALTIMORE MD
— 443-402 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 EDGEWOOD MD
— 443-406 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 ELKTON MD
— 443-412 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 8 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 CHURCHVL MD
— 443-417 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 FALLSTON MD
— 443-424 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 CARDIFF MD
— 443-425 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 PARKVILLE MD
— 443-441 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 8 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 GLENWOOD MD
— 443-457 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 BRYNPKLNCM MD
— 443-489 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 7 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 CHASE MD
— 443-502 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 HAVREGRACE MD
— 443-507 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX · 7 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 HAMPSTEAD MD
— 443-533 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 JARRETTSVL MD
— 443-620 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 WATERLO238 MD
— 443-648 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 ESSEX MD
— 443-671 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 NEWWINDSOR MD
— 443-672 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 PARKTON MD
— 443-674 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 NORTH EAST MD
— 443-679 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 7 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 SEVERN MD
— 443-693 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 PERRYVILLE MD
— 443-698 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 7 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 ODENTON MD
— 443-731 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 7 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 PT DEPOSIT MD
— 443-732 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 SILVER RUN MD
— 443-733 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 WATERLO238 MD
— 443-784 0–9 XXXall 10 · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 ARGRGBSNIS MD
— 443-880 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 SALISBURY MD
— 443-883 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 GLENBURNIE MD
— 443-886 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 COCKEYSVL MD
— 443-896 3XXX4XXX6XXX7XXX8XXX which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 COLUMBIA MD
— 443-914 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 7 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 WORTHINGTN MD
— 443-918 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 TANEYTOWN MD
— 443-920 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 SYKESVILLE MD
— 443-937 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 UNION BDG MD
— 443-942 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 2 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 SEVERNA PK MD
— 443-943 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 SPARROWSPT MD
— 443-974 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 2 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 WESTMINSTR MD

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.