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 817
SOUTHWESTERN BELL 302
NEW CINGULAR WIRELESS PCS, LLC - IL 88
T-MOBILE USA, INC. 54
LEVEL 3 COMMUNICATIONS, LLC - TX 45
ONVOY, LLC - TX 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
— 817-282 not yet reported which blocks → SOUTHWESTERN BELL 9533 EULESS TX
— 817-283 not yet reported which blocks → SOUTHWESTERN BELL 9533 EULESS TX
— 817-284 not yet reported which blocks → SOUTHWESTERN BELL 9533 ATLAS TX
— 817-285 2XXX5XXX7XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 EULESS TX
— 817-286 0–9 XXXall 10 · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - TX 6114 ATLAS TX
— 817-287 1XXX8XXX9XXX which blocks → LEVEL 3 OF TELECOM OF TEXAS, LLC - TX 7516 ARLINGTON TX
— 817-288 none assigned yet which blocks → LEVEL 3 OF TELECOM OF TEXAS, LLC - TX 7516 FORT WORTH TX
— 817-289 not yet reported which blocks → U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 671J FORT WORTH TX
— 817-291 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ARLINGTON TX
— 817-292 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-293 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-294 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-295 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-296 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ARLINGTON TX
— 817-297 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-298 0XXX1XXX2XXX4XXX6XXX7XXX8XXX9XXX which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-299 none assigned yet which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-300 none assigned yet which blocks → METROPCS, INC. 5562 ARLINGTON TX
— 817-301 2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX which blocks → GRANDE COMMUNICATIONS NETWORKS, INC. - TX 7670 ARLINGTON TX
— 817-302 6XXX which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 FORT WORTH TX
— 817-303 9XXX which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-304 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 WEATHERFD TX
— 817-305 1XXX2XXX3XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → FRONTIER SOUTHWEST INC DBA FRONTIER COMM OF TEXAS 4344 GRAPEVINE TX
— 817-306 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-307 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ARLINGTON TX
— 817-308 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ARLINGTON TX
— 817-309 1XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → TEXAS WINDSTREAM, LLC 2153 GODLEY TX
— 817-310 1XXX2XXX7XXX8XXX9XXX · 3 holders which blocks → SOUTHWESTERN BELL TELEPHONE COMPANY - TX 7726 GRAPEVINE TX
— 817-311 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX TX
— 817-312 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ARLINGTON TX
— 817-313 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ARLINGTON TX
— 817-314 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-315 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-316 not yet reported which blocks → SOUTHWESTERN BELL 9533 GLENDALE TX
— 817-317 1XXX6XXX8XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-318 0XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 EULESS TX
— 817-319 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 GLENDALE TX
— 817-320 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - TX 6506 ARLINGTON TX
— 817-321 none assigned yet which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-322 not yet reported which blocks → GRANDE COMMUNICATIONS NETWORKS, INC. - TX 7670 KELLER TX
— 817-323 0XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-326 7XXX which blocks → TEXAS WINDSTREAM, LLC 2153 ACTON TX
— 817-327 not yet reported which blocks → SPOK, INC. 6630 ARLINGTON TX
— 817-328 0XXX9XXX · 2 holders which blocks → ONVOY, LLC - TX 903C GRAPEVINE TX
— 817-329 not yet reported which blocks → FRONTIER SOUTHWEST INC DBA FRONTIER COMM OF TEXAS 4344 GRAPEVINE TX
— 817-330 3XXX4XXX6XXX8XXX9XXX · 4 holders which blocks → ONVOY, LLC - TX 903C KENNEDALE TX
— 817-332 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-333 4XXX7XXX8XXX9XXX which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-334 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-335 0XXX which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX

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.