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 503
QWEST CORPORATION 222
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
— 503-280 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-281 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-282 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-283 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-284 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-285 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-286 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-287 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-288 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-289 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-291 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-292 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-293 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-294 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-295 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-296 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-297 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-299 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-304 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-306 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-315 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-316 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-321 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-323 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-325 not yet reported which blocks → QWEST CORPORATION 9638 ASTORIA OR
— 503-326 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-331 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-335 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-338 none assigned yet which blocks → QWEST CORPORATION 9638 ASTORIA OR
— 503-340 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-346 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-353 not yet reported which blocks → QWEST CORPORATION 9638 CLACKAMAS OR
— 503-361 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-362 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-363 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-364 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-365 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-366 not yet reported which blocks → QWEST CORPORATION 9638 ST HELENS OR
— 503-370 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-371 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-373 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-375 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-378 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-384 2XXX8XXX · 2 holders which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-390 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-391 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-393 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-397 not yet reported which blocks → QWEST CORPORATION 9638 ST HELENS OR
— 503-399 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-401 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR

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.