NumberResearch Membership · Data 09/20/2026

Thousands-blocks in 571-399

This prefix’s ten 1,000-number blocks and who holds each — 10 on record · from the daily NANPA thousands-block report, 09/20/2026

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

The ten 1,000-number thousand-blocks inside prefix 571-399 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 571 blocks

Most active assignees, all time — NPA 571
YMAX COMMUNICATIONS CORP. OF VIRGINIA - VA 3
BANDWIDTH.COM CLEC, LLC - VA 3
PEERLESS NETWORK OF VIRGINIA, LLC - VA 1
ONVOY, LLC - VA 1
MCIMETRO ACCESS TRANSMISSION SERVICES 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
2009-02-03 571-399-0XXX 0000–0999Assigned YMAX COMMUNICATIONS CORP. OF VIRGINIA - VA 367E INDENDNTHL VA
2009-02-03 571-399-1XXX 1000–1999Assigned YMAX COMMUNICATIONS CORP. OF VIRGINIA - VA 367E INDENDNTHL VA
2009-02-03 571-399-2XXX 2000–2999Assigned YMAX COMMUNICATIONS CORP. OF VIRGINIA - VA 367E INDENDNTHL VA
2017-03-09 571-399-3XXX 3000–3999Assigned ONVOY, LLC - VA 138E INDENDNTHL VA
2016-08-18 571-399-4XXX 4000–4999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 INDENDNTHL VA
2010-01-21 571-399-5XXX 5000–5999Assigned BANDWIDTH.COM CLEC, LLC - VA 079F INDENDNTHL VA
2010-10-01 571-399-6XXX 6000–6999Assigned BANDWIDTH.COM CLEC, LLC - VA 079F INDENDNTHL VA
2012-04-16 571-399-7XXX 7000–7999Assigned COMCAST IP PHONE, LLC 318J INDENDNTHL VA
2012-05-17 571-399-8XXX 8000–8999Assigned BANDWIDTH.COM CLEC, LLC - VA 079F INDENDNTHL VA
2013-04-08 571-399-9XXX 9000–9999Assigned PEERLESS NETWORK OF VIRGINIA, LLC - VA 275G INDENDNTHL VA

Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/20/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.