NumberResearch Membership · Data 09/19/2026

Recent thousands-block assignments

0 blocks assigned in the last 30 days · from the daily NANPA thousands-block report, 09/19/2026

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

Most carrier growth happens here, not at the prefix level: under number pooling, carriers receive individual 1,000-number blocks (e.g. 626-470-0XXX) within already-assigned prefixes. Assignments are initial assignments — the current serving carrier of individual numbers may differ due to portability.

Most active assignees, all time — NPA 231
AT&T ENTERPRISES, LLC 46
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
2023-08-25 231-367-4XXX 4000–4999Assigned AT&T ENTERPRISES, LLC 516C WOLVERINE MI
2023-08-25 231-466-1XXX 1000–1999Assigned AT&T ENTERPRISES, LLC 516C EVART MI
2023-08-25 231-475-7XXX 7000–7999Assigned AT&T ENTERPRISES, LLC 516C MANTON MI
2023-08-25 231-800-7XXX 7000–7999Assigned AT&T ENTERPRISES, LLC 516C LUTHER MI
2013-10-10 231-386-3XXX 3000–3999Assigned AT&T ENTERPRISES, LLC 516C NORTHPORT MI
2013-01-28 231-729-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C IRONS MI
2013-01-28 231-916-7XXX 7000–7999Assigned AT&T ENTERPRISES, LLC 516C MANCELONA MI
2012-11-07 231-299-3XXX 3000–3999Assigned AT&T ENTERPRISES, LLC 516C MANISTEE MI
2012-11-07 231-497-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C BOYNE CITY MI
2012-11-07 231-680-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C REED CITY MI
2012-11-07 231-758-1XXX 1000–1999Assigned AT&T ENTERPRISES, LLC 516C PETOSKEY MI
2011-08-17 231-403-7XXX 7000–7999Assigned AT&T ENTERPRISES, LLC 516C WILLIAMSBG MI
2011-08-17 231-427-7XXX 7000–7999Assigned AT&T ENTERPRISES, LLC 516C MACKINAWCY MI
2011-08-11 231-238-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C INDIAN RIV MI
2011-08-11 231-303-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C NEWAYGO MI
2011-08-11 231-335-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C FREMONT MI
2011-08-11 231-338-3XXX 3000–3999Assigned AT&T ENTERPRISES, LLC 516C BALDWIN MI
2011-08-11 231-354-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C CORAL MI
2011-08-11 231-388-8XXX 8000–8999Assigned AT&T ENTERPRISES, LLC 516C LE ROY MI
2011-08-11 231-389-7XXX 7000–7999Assigned AT&T ENTERPRISES, LLC 516C HARRIETTA MI
2011-08-11 231-399-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C FRANKFORT MI
2011-08-11 231-412-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C HARBOR SPG MI
2011-08-11 231-437-2XXX 2000–2999Assigned AT&T ENTERPRISES, LLC 516C CHARLEVOIX MI
2011-08-11 231-462-7XXX 7000–7999Assigned AT&T ENTERPRISES, LLC 516C FOUNTAIN MI
2011-08-11 231-498-6XXX 6000–6999Assigned AT&T ENTERPRISES, LLC 516C ELK RAPIDS MI
2011-08-11 231-508-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C ONEKAMA MI
2011-08-11 231-518-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C KALKASKA MI
2011-08-11 231-535-7XXX 7000–7999Assigned AT&T ENTERPRISES, LLC 516C WALLOON LK MI
2011-08-11 231-536-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C EASTJORDAN MI
2011-08-11 231-539-9XXX 9000–9999Assigned AT&T ENTERPRISES, LLC 516C PELLSTON MI
2011-08-11 231-570-7XXX 7000–7999Assigned AT&T ENTERPRISES, LLC 516C FIFE LAKE MI
2011-08-11 231-651-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C BEULAH MI
2011-08-11 231-660-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C BIG RAPIDS MI
2011-08-11 231-714-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C TRAVERSECY MI
2011-08-11 231-743-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C MARION MI
2011-08-11 231-774-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C INTERLOCHN MI
2011-08-11 231-790-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C FREESOIL MI
2011-08-11 231-793-6XXX 6000–6999Assigned AT&T ENTERPRISES, LLC 516C WHITECLOUD MI
2011-08-11 231-803-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C MORLEY MI
2011-08-11 231-825-6XXX 6000–6999Assigned AT&T ENTERPRISES, LLC 516C MCBAIN MI
2011-08-11 231-829-2XXX 2000–2999Assigned AT&T ENTERPRISES, LLC 516C TUSTIN MI
2011-08-11 231-936-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C SCOTTVILLE MI
2011-08-11 231-942-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C CADILLAC MI
2011-08-11 231-994-5XXX 5000–5999Assigned AT&T ENTERPRISES, LLC 516C LKLEELANAU MI
2011-05-18 231-445-7XXX 7000–7999Assigned AT&T ENTERPRISES, LLC 516C CHEBOYGAN MI
2011-01-19 231-674-2XXX 2000–2999Assigned AT&T ENTERPRISES, LLC 516C GRANT 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.