NumberResearch Membership · Data 09/19/2026

Thousands-blocks in 443-433

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 443-433 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
MCIMETRO ACCESS TRANSMISSION SERVICES LLC 4
NEW CINGULAR WIRELESS PCS, LLC - DC 3
PAETEC ITEL, LLC 2
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
— 443-433-0XXX 0000–0999Reserved MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 ANNAPOLIS MD
2005-09-08 443-433-1XXX 1000–1999Assigned PAETEC ITEL, LLC 829J ANNAPOLIS MD
2006-02-17 443-433-2XXX 2000–2999Assigned NEW CINGULAR WIRELESS PCS, LLC - DC 4036 ANNAPOLIS MD
2005-03-23 443-433-3XXX 3000–3999Assigned PAETEC ITEL, LLC 829J ANNAPOLIS MD
— 443-433-4XXX 4000–4999Reserved MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 ANNAPOLIS MD
— 443-433-5XXX 5000–5999Reserved MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 ANNAPOLIS MD
2006-02-17 443-433-6XXX 6000–6999Assigned NEW CINGULAR WIRELESS PCS, LLC - DC 4036 ANNAPOLIS MD
— 443-433-7XXX 7000–7999Reserved MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 ANNAPOLIS MD
2006-02-17 443-433-8XXX 8000–8999Assigned NEW CINGULAR WIRELESS PCS, LLC - DC 4036 ANNAPOLIS MD
2011-08-09 443-433-9XXX 9000–9999Assigned OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 6855 ANNAPOLIS 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.