NumberResearch Membership · Data 09/19/2026

Thousands-blocks in 231-529

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 231-529 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 231 blocks

Most active assignees, all time — NPA 231
BRIGHTSPEED OF MICHIGAN, LLC 7
ONVOY, LLCV - MI 1
LEVEL 3 COMMUNICATIONS, LLC - MI 1
CENTURYLINK COMMUNICATIONS, 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
— 231-529-0XXX 0000–0999Reserved BRIGHTSPEED OF MICHIGAN, LLC 0702 BRUTUS MI
— 231-529-1XXX 1000–1999Reserved BRIGHTSPEED OF MICHIGAN, LLC 0702 BRUTUS MI
— 231-529-2XXX 2000–2999Reserved BRIGHTSPEED OF MICHIGAN, LLC 0702 BRUTUS MI
— 231-529-3XXX 3000–3999Reserved BRIGHTSPEED OF MICHIGAN, LLC 0702 BRUTUS MI
2015-09-17 231-529-4XXX 4000–4999Assigned CENTURYLINK COMMUNICATIONS, LLC 508J BRUTUS MI
2019-08-06 231-529-5XXX 5000–5999Assigned ONVOY, LLCV - MI 543C BRUTUS MI
— 231-529-6XXX 6000–6999Reserved BRIGHTSPEED OF MICHIGAN, LLC 0702 BRUTUS MI
2019-06-13 231-529-7XXX 7000–7999Assigned LEVEL 3 COMMUNICATIONS, LLC - MI 6120 BRUTUS MI
— 231-529-8XXX 8000–8999Reserved BRIGHTSPEED OF MICHIGAN, LLC 0702 BRUTUS MI
— 231-529-9XXX 9000–9999Reserved BRIGHTSPEED OF MICHIGAN, LLC 0702 BRUTUS MI

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.