NumberResearch Membership · Data 09/20/2026

Thousands-blocks in 575-308

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 575-308 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 575 blocks

Most active assignees, all time — NPA 575
T-MOBILE USA, INC. 5
METROPCS, INC. 2
LEVEL 3 COMMUNICATIONS, LLC - NM 2
TERRA NOVA TELECOM INC. 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
Clear Download CSV ↓
Recent thousands-block assignments
AssignedThousands-blockLast 4 digitsStatusAssigneeOCNRate centerState
2004-10-18 575-308-0XXX 0000–0999Assigned LEVEL 3 COMMUNICATIONS, LLC - NM 5470 ARTESIA NM
— 575-308-1XXX 1000–1999Reserved T-MOBILE USA, INC. 6529 ARTESIA NM
2007-09-10 575-308-2XXX 2000–2999Assigned METROPCS, INC. 5562 ARTESIA NM
— 575-308-3XXX 3000–3999Reserved T-MOBILE USA, INC. 6529 ARTESIA NM
2023-07-11 575-308-4XXX 4000–4999Assigned TERRA NOVA TELECOM INC. 145J ARTESIA NM
2008-09-05 575-308-5XXX 5000–5999Assigned LEVEL 3 COMMUNICATIONS, LLC - NM 5470 ARTESIA NM
2006-09-06 575-308-6XXX 6000–6999Assigned T-MOBILE USA, INC. 6529 ARTESIA NM
2006-01-03 575-308-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 ARTESIA NM
2004-10-20 575-308-8XXX 8000–8999Assigned METROPCS, INC. 5562 ARTESIA NM
— 575-308-9XXX 9000–9999Reserved T-MOBILE USA, INC. 6529 ARTESIA NM

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.