NumberResearch Membership · Data 09/19/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/19/2026

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
— 231-258 not yet reported which blocks → MICHIGAN BELL TEL CO 9323 KALKASKA MI
— 231-263 8XXX9XXX · 2 holders which blocks → BRIGHTSPEED OF NORTHERN MICHIGAN, INC 0705 KINGSLEY MI
— 231-264 1XXX2XXX3XXX4XXX7XXX · 5 holders which blocks → MICHIGAN BELL TEL CO 9323 ELK RAPIDS MI
— 231-266 0XXX1XXX3XXX4XXX6XXX7XXX9XXX · 3 holders which blocks → MICHIGAN BELL TEL CO 9323 IRONS MI
— 231-267 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX · 8 holders which blocks → MICHIGAN BELL TEL CO 9323 WILLIAMSBG MI
— 231-269 not yet reported which blocks → ACE TEL. CO. OF MICHIGAN, INC. 0704 BUCKLEY MI
— 231-271 not yet reported which blocks → BRIGHTSPEED OF MICHIGAN, LLC 0702 SUTTONSBAY MI
— 231-274 not yet reported which blocks → AMERICAN MESSAGING SERVICES, LLC 9748 TRAVERSECY MI
— 231-275 not yet reported which blocks → BRIGHTSPEED OF MICHIGAN, LLC 0702 LAKE ANN MI
— 231-276 1XXX2XXX3XXX8XXX · 3 holders which blocks → MICHIGAN BELL TEL CO 9323 INTERLOCHN MI
— 231-282 6XXX7XXX9XXX · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 GRANT MI
— 231-286 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 MUSKEGON MI
— 231-287 4XXX5XXX · 2 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 BIG RAPIDS MI
— 231-290 2XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 INDIAN RIV MI
— 231-301 6XXX7XXX8XXX9XXX · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 HART MI
— 231-302 not yet reported which blocks → BANDWIDTH.COM CLEC, LLC - MI 991E PETOSKEY MI
— 231-305 not yet reported which blocks → TELNET WORLDWIDE, INC. 817J BIG RAPIDS MI
— 231-306 not yet reported which blocks → TELNET WORLDWIDE, INC. 817J CADILLAC MI
— 231-307 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 MORLEY MI
— 231-308 not yet reported which blocks → TELNET WORLDWIDE, INC. 817J CHARLEVOIX MI
— 231-309 not yet reported which blocks → TELNET WORLDWIDE, INC. 817J MANISTEE MI
— 231-311 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX MI
— 231-312 not yet reported which blocks → TELNET WORLDWIDE, INC. 817J FRANKFORT MI
— 231-313 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 TRAVERSECY MI
— 231-314 not yet reported which blocks → TELNET WORLDWIDE, INC. 817J KALKASKA MI
— 231-315 not yet reported which blocks → SPOK, INC. 6630 MUSKEGON MI
— 231-316 not yet reported which blocks → TELNET WORLDWIDE, INC. 817J LUDINGTON MI
— 231-317 not yet reported which blocks → SPOK, INC. 6630 BOYNE CITY MI
— 231-318 not yet reported which blocks → SPOK, INC. 6630 TRAVERSECY MI
— 231-319 not yet reported which blocks → TELNET WORLDWIDE, INC. 817J MACKINAWCY MI
— 231-322 0XXX1XXX3XXX5XXX7XXX8XXX9XXX · 5 holders which blocks → FRONTIER NORTH, INC. - MI 0695 TRCHRIVBDG MI
— 231-323 not yet reported which blocks → BANDWIDTH.COM CLEC, LLC - MI 991E EASTJORDAN MI
— 231-325 not yet reported which blocks → BRIGHTSPEED OF MICHIGAN, LLC 0702 HONOR MI
— 231-326 not yet reported which blocks → BRIGHTSPEED OF MICHIGAN, LLC 0702 GLEN LAKE MI
— 231-327 4XXX8XXX which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 MUSKEGON MI
— 231-328 6XXX which blocks → BRIGHTSPEED OF MICHIGAN, LLC 0702 MERRITT MI
— 231-329 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 MUSKEGON MI
— 231-331 0XXX1XXX2XXX3XXX5XXX8XXX9XXX · 5 holders which blocks → FRONTIER NORTH, INC. - MI 0695 ALDEN MI
— 231-332 not yet reported which blocks → TELNET WORLDWIDE, INC. 817J MUSKEGON MI
— 231-334 not yet reported which blocks → BRIGHTSPEED OF MICHIGAN, LLC 0702 GLEN LAKE MI
— 231-335 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 FREMONT MI
— 231-336 not yet reported which blocks → SPOK, INC. 6630 LUDINGTON MI
— 231-337 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 MCBAIN MI
— 231-338 0XXX3XXX6XXX · 3 holders which blocks → BANDWIDTH.COM CLEC, LLC - MI 991E BALDWIN MI
— 231-339 not yet reported which blocks → AMERICAN MESSAGING SERVICES, LLC 9748 MUSKEGON MI
— 231-342 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI 6003 TRAVERSECY MI
— 231-343 none assigned yet which blocks → OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC 2964 MUSKEGON MI
— 231-344 not yet reported which blocks → TELNET WORLDWIDE, INC. 817J PETOSKEY MI
— 231-345 3XXX6XXX · 2 holders which blocks → BANDWIDTH.COM CLEC, LLC - MI 991E REED CITY MI
— 231-346 not yet reported which blocks → TELNET WORLDWIDE, INC. 817J TRAVERSECY MI

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/19/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.