NumberResearch Membership · Data 09/20/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/20/2026

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

The Code holder is who opened each NPA-NXX prefix — not necessarily who holds the numbers. A prefix is 10,000 numbers, but under pooling its ten 1,000-number blocks are handed out individually, often to different carriers; the code holder may hold only one block, or none. The Thousands-blocks column shows how the ten blocks are really split — click which blocks → to see who holds each 1,000-number block and its last-4-digit range. Assignments are initial assignments; the current serving carrier may differ due to portability.

Most active assignees, all time — NPA 231
NEW CINGULAR WIRELESS PCS, LLC - IL 72
MICHIGAN BELL TEL CO 72
FRONTIER NORTH, INC. - MI 52
ONVOY, LLCV - MI 49
TELNET WORLDWIDE, INC. 43
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 NPA-NXX prefix assignments
AssignedNPA-NXXThousands-blocks taken (last-4 opening)Code holderOCNRate centerState
— 231-871 1XXX3XXX6XXX8XXX9XXX · 4 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 BEULAH MI
— 231-872 2XXX5XXX6XXX8XXX9XXX · 4 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 REED CITY MI
— 231-873 not yet reported which blocks → FRONTIER NORTH, INC. - MI 0695 HART MI
— 231-875 6XXX which blocks → BANDWIDTH.COM CLEC, LLC - MI 991E FRUITPORT MI
— 231-876 8XXX which blocks → MICHIGAN BELL TEL CO 9323 CADILLAC MI
— 231-877 not yet reported which blocks → 123.NET, LLC 2550 NORTHPORT MI
— 231-879 1XXX2XXX5XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → MICHIGAN BELL TEL CO 9323 FIFE LAKE MI
— 231-881 8XXX9XXX · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 PETOSKEY MI
— 231-882 6XXX which blocks → MICHIGAN BELL TEL CO 9323 BEULAH MI
— 231-883 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 TRAVERSECY MI
— 231-884 3XXX4XXX5XXX6XXX7XXX8XXX9XXX which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 CADILLAC MI
— 231-885 7XXX which blocks → ACE TEL. CO. OF MICHIGAN, INC. 0704 MESICK MI
— 231-886 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 KALKASKA MI
— 231-887 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 MANISTEE MI
— 231-889 1XXX2XXX6XXX7XXX8XXX · 5 holders which blocks → MICHIGAN BELL TEL CO 9323 ONEKAMA MI
— 231-890 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 TRAVERSECY MI
— 231-893 not yet reported which blocks → FRONTIER NORTH, INC. - MI 0695 WHITEHALL MI
— 231-894 0XXX which blocks → FRONTIER NORTH, INC. - MI 0695 WHITEHALL MI
— 231-898 7XXX which blocks → CARR TEL. CO. 0683 CARR MI
— 231-906 not yet reported which blocks → MI
— 231-911 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX MI
— 231-920 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 CADILLAC MI
— 231-922 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 TRAVERSECY MI
— 231-924 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 FREMONT MI
— 231-928 5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → MICHIGAN BELL TEL CO 9323 FREMONT MI
— 231-929 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 TRAVERSECY MI
— 231-932 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 TRAVERSECY MI
— 231-933 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 TRAVERSECY MI
— 231-935 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 TRAVERSECY MI
— 231-937 0XXX1XXX2XXX3XXX · 4 holders which blocks → FRONTIER NORTH, INC. - MI 0695 HOWARDCITY MI
— 231-938 6XXX which blocks → MICHIGAN BELL TEL CO 9323 TRAVERSECY MI
— 231-941 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 TRAVERSECY MI
— 231-943 1XXX2XXX6XXX · 2 holders which blocks → MICHIGAN BELL TEL CO 9323 TRAVERSECY MI
— 231-944 0–9 XXXall 10 · 3 holders which blocks → CYNERGYCOMM.NET, INC. - MI 9245 TRAVERSECY MI
— 231-946 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 TRAVERSECY MI
— 231-947 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 TRAVERSECY MI
— 231-950 not yet reported which blocks → MI
— 231-955 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 MUSKEGON MI
— 231-958 not yet reported which blocks → MI
— 231-959 not yet reported which blocks → MI
— 231-972 not yet reported which blocks → BRIGHTSPEED OF CENTRAL MICHIGAN, INC 0671 MECOSTA MI
— 231-976 not yet reported which blocks → MI
— 231-981 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → FRONTIER NORTH, INC. - MI 0695 WHITEHALL MI
— 231-988 not yet reported which blocks → MI
— 231-989 not yet reported which blocks → MI
— 231-995 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 TRAVERSECY MI

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/20/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.