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
— 817-394 8XXX which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 ARLINGTON TX
— 817-395 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 GLENDALE TX
— 817-396 1XXX2XXX5XXX6XXX7XXX8XXX · 2 holders which blocks → TEXAS WINDSTREAM, LLC 2153 CRESSON TX
— 817-397 not yet reported which blocks → GRANDE COMMUNICATIONS NETWORKS, INC. - TX 7670 KELLER TX
— 817-398 3XXX4XXX5XXX8XXX9XXX · 3 holders which blocks → GRANDE COMMUNICATIONS NETWORKS, INC. - TX 7670 NRICHLDHLS TX
— 817-399 not yet reported which blocks → SOUTHWESTERN BELL 9533 EULESS TX
— 817-401 none assigned yet which blocks → T-MOBILE USA, INC. 6529 ARLINGTON TX
— 817-403 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - TX 6506 DENTON TX
— 817-404 2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-405 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - TX 6114 MANSFIELD TX
— 817-406 0–9 XXXall 10 · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - TX 004F AZLE TX
— 817-407 not yet reported which blocks → AMERICAN MESSAGING SERVICES, LLC 9748 ARLINGTON TX
— 817-408 0XXX5XXX6XXX which blocks → SOUTHWESTERN BELL 9533 GRANBURY TX
— 817-409 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - TX 6114 ALVARADO TX
— 817-410 not yet reported which blocks → FRONTIER SOUTHWEST INC DBA FRONTIER COMM OF TEXAS 4344 GRAPEVINE TX
— 817-411 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX TX
— 817-412 0XXX1XXX3XXX4XXX7XXX8XXX9XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-413 1XXX7XXX8XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-414 not yet reported which blocks → SPOK, INC. 6630 GRAPEVINE TX
— 817-415 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-416 not yet reported which blocks → FRONTIER SOUTHWEST INC DBA FRONTIER COMM OF TEXAS 4344 GRAPEVINE TX
— 817-417 9XXX which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-418 not yet reported which blocks → AMERICAN MESSAGING SERVICES, LLC 9748 ARLINGTON TX
— 817-419 not yet reported which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-420 0XXX2XXX3XXX4XXX6XXX7XXX9XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-421 not yet reported which blocks → FRONTIER SOUTHWEST INC DBA FRONTIER COMM OF TEXAS 4344 GRAPEVINE TX
— 817-423 3XXX6XXX7XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-424 not yet reported which blocks → FRONTIER SOUTHWEST INC DBA FRONTIER COMM OF TEXAS 4344 GRAPEVINE TX
— 817-426 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-427 5XXX which blocks → SOUTHWESTERN BELL 9533 NRICHLDHLS TX
— 817-428 not yet reported which blocks → SOUTHWESTERN BELL 9533 NRICHLDHLS TX
— 817-429 not yet reported which blocks → SOUTHWESTERN BELL 9533 GLENDALE TX
— 817-430 not yet reported which blocks → SOUTHWESTERN BELL 9533 ROANOKE TX
— 817-431 not yet reported which blocks → FRONTIER SOUTHWEST INC DBA FRONTIER COMM OF TEXAS 4344 KELLER TX
— 817-433 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-435 0–9 XXXall 10 · 6 holders which blocks → PAETEC ITEL, LLC 829J MANSFIELD TX
— 817-436 not yet reported which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-438 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX · 3 holders which blocks → AT&T - LOCAL 7421 EULESS TX
— 817-439 6XXX7XXX9XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-441 0XXX3XXX which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-442 2XXX3XXX6XXX7XXX · 2 holders which blocks → FRONTIER SOUTHWEST INC DBA FRONTIER COMM OF TEXAS 4344 GRAPEVINE TX
— 817-443 1XXX2XXX4XXX5XXX7XXX8XXX which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-444 not yet reported which blocks → FRONTIER SOUTHWEST INC DBA FRONTIER COMM OF TEXAS 4344 AZLE TX
— 817-446 9XXX which blocks → SOUTHWESTERN BELL 9533 GLENDALE TX
— 817-447 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-448 1XXX2XXX3XXX4XXX5XXX7XXX which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-449 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-451 not yet reported which blocks → SOUTHWESTERN BELL 9533 GLENDALE TX
— 817-453 not yet reported which blocks → SOUTHWESTERN BELL 9533 MANSFIELD TX
— 817-454 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 GLENDALE 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.