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 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
— 817-336 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-337 not yet reported which blocks → FRONTIER SOUTHWEST INC DBA FRONTIER COMM OF TEXAS 4344 KELLER TX
— 817-338 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-339 6XXX which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-340 not yet reported which blocks → SPOK, INC. 6630 ARLINGTON TX
— 817-341 6XXX9XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 WEATHERFD TX
— 817-342 not yet reported which blocks → LEVEL 3 OF TELECOM OF TEXAS, LLC - TX 7516 ARLINGTON TX
— 817-343 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 GLENDALE TX
— 817-344 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → AT&T - LOCAL 7421 FORT WORTH TX
— 817-345 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 7 holders which blocks → AT&T - LOCAL 7421 NRICHLDHLS TX
— 817-346 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-347 0XXX which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-348 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-349 0–9 XXXall 10 · 5 holders which blocks → CHARTER IP ENABLED SERVICES, LLC 792K FORT WORTH TX
— 817-350 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-351 not yet reported which blocks → SPOK, INC. 6630 ARLINGTON TX
— 817-352 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-353 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 2 holders which blocks → AT&T - LOCAL 7421 FORT WORTH TX
— 817-354 not yet reported which blocks → SOUTHWESTERN BELL 9533 EULESS TX
— 817-355 not yet reported which blocks → SOUTHWESTERN BELL 9533 EULESS TX
— 817-356 not yet reported which blocks → TELETOUCH COMMUNICATIONS, INC. 6591 ARLINGTON TX
— 817-357 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX9XXX · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - TX 6506 CLEBURNE TX
— 817-358 not yet reported which blocks → SOUTHWESTERN BELL 9533 EULESS TX
— 817-359 not yet reported which blocks → SOUTHWESTERN BELL 9533 EULESS TX
— 817-360 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 GLENDALE TX
— 817-361 2XXX3XXX4XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-362 not yet reported which blocks → GRANDE COMMUNICATIONS NETWORKS, INC. - TX 7670 EULESS TX
— 817-365 not yet reported which blocks → GRANDE COMMUNICATIONS NETWORKS, INC. - TX 7670 FORT WORTH TX
— 817-366 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ARLINGTON TX
— 817-367 8XXX9XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-368 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ARLINGTON TX
— 817-369 3XXX4XXX5XXX8XXX9XXX · 3 holders which blocks → GRANDE COMMUNICATIONS NETWORKS, INC. - TX 7670 NRICHLDHLS TX
— 817-370 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-371 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ARLINGTON TX
— 817-373 1XXX5XXX7XXX · 3 holders which blocks → TEXAS WINDSTREAM, LLC 2153 RIO VISTA TX
— 817-376 7XXX9XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-377 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-378 4XXX6XXX7XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-379 7XXX8XXX · 2 holders which blocks → FRONTIER SOUTHWEST INC DBA FRONTIER COMM OF TEXAS 4344 KELLER TX
— 817-380 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → GRANDE COMMUNICATIONS NETWORKS, INC. - TX 7670 KELLER TX
— 817-381 0–9 XXXall 10 · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - TX 6114 RENO TX
— 817-382 0–9 XXXall 10 · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - TX 6114 SPRINGTOWN TX
— 817-383 0–9 XXXall 10 · 2 holders which blocks → ONVOY, LLC - TX 903C RHOME TX
— 817-385 1XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → SOUTHWESTERN BELL 9533 ARLINGTON TX
— 817-386 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX9XXX · 3 holders which blocks → CHARTER IP ENABLED SERVICES, LLC 792K FORT WORTH TX
— 817-387 not yet reported which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-389 1XXX4XXX5XXX6XXX7XXX8XXX · 2 holders which blocks → TEXAS WINDSTREAM, LLC 2153 GODLEY TX
— 817-390 0XXX which blocks → SOUTHWESTERN BELL 9533 FORT WORTH TX
— 817-391 2XXX4XXX5XXX7XXX8XXX9XXX · 3 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 EULESS TX
— 817-393 2XXX3XXX5XXX6XXX7XXX9XXX · 3 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 NRICHLDHLS TX

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.