NumberResearch Membership · Data 09/19/2026

Thousands-blocks in 443-666

This prefix’s ten 1,000-number blocks and who holds each — 10 on record · from the daily NANPA thousands-block report, 09/19/2026

Full prefixes (NXX) Thousands-blocks (1,000-number pools)

The ten 1,000-number thousand-blocks inside prefix 443-666 and who was initially assigned each. Under pooling these blocks often belong to different carriers — the single prefix-level “assignee” is usually just the pool / code holder, not who holds the numbers. ← all 443 blocks

Most active assignees, all time — NPA 443
NEW CINGULAR WIRELESS PCS, LLC - DC 2
TELNYX LLC 1
TELEPORT COMMUNICATIONS AMERICA, LLC - MD 1
PAETEC ITEL, LLC 1
OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 1
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 thousands-block assignments
AssignedThousands-blockLast 4 digitsStatusAssigneeOCNRate centerState
2018-01-15 443-666-0XXX 0000–0999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 6395 CHESTERTN MD
2021-03-29 443-666-1XXX 1000–1999Assigned OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 CHESTERTN MD
2014-10-13 443-666-2XXX 2000–2999Assigned PAETEC ITEL, LLC 829J CHESTERTN MD
2012-05-31 443-666-3XXX 3000–3999Assigned LEVEL 3 COMMUNICATIONS, LLC - MD 6119 CHESTERTN MD
2016-02-12 443-666-4XXX 4000–4999Assigned NEW CINGULAR WIRELESS PCS, LLC - DC 4036 CHESTERTN MD
2019-04-16 443-666-5XXX 5000–5999Assigned CORE COMMUNICATIONS, INC.- MD 2593 CHESTERTN MD
2014-09-24 443-666-6XXX 6000–6999Assigned TELEPORT COMMUNICATIONS AMERICA, LLC - MD 7325 CHESTERTN MD
2018-07-30 443-666-7XXX 7000–7999Assigned NEW CINGULAR WIRELESS PCS, LLC - DC 4036 CHESTERTN MD
2017-08-31 443-666-8XXX 8000–8999Assigned TELNYX LLC 073H CHESTERTN MD
2021-04-16 443-666-9XXX 9000–9999Assigned METROPCS, INC. 5562 CHESTERTN MD

Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/19/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.