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
Clear Download CSV ↓
Recent NPA-NXX prefix assignments
AssignedNPA-NXXThousands-blocks taken (last-4 opening)Code holderOCNRate centerState
— 503-402 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-408 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-412 8XXX9XXX which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-413 0XXX9XXX · 2 holders which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-414 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-415 0XXX1XXX9XXX which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-417 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-418 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-423 7XXX which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-425 9XXX which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-436 3XXX4XXX5XXX6XXX7XXX · 3 holders which blocks → QWEST CORPORATION 9638 CANNON BCH OR
— 503-441 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-450 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-452 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-455 4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → QWEST CORPORATION 9638 WESTPORT OR
— 503-460 7XXX which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-463 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-464 6XXX which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-471 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-478 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-493 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-494 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-497 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-499 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-513 not yet reported which blocks → QWEST CORPORATION 9638 CLACKAMAS OR
— 503-525 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-528 4XXX6XXX which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-534 6XXX which blocks → QWEST CORPORATION 9638 CLACKAMAS OR
— 503-540 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-552 not yet reported which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-553 9XXX which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-556 not yet reported which blocks → QWEST CORPORATION 9638 RAINIER OR
— 503-557 not yet reported which blocks → QWEST CORPORATION 9638 CLACKAMAS OR
— 503-566 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-571 not yet reported which blocks → QWEST CORPORATION 9638 CLACKAMAS OR
— 503-576 0XXX1XXX9XXX · 3 holders which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-581 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-584 1XXX which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-585 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-587 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-588 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-589 not yet reported which blocks → QWEST CORPORATION 9638 SALEM OR
— 503-606 6XXX7XXX8XXX · 2 holders which blocks → QWEST CORPORATION 9638 DALLAS OR
— 503-621 2XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → QWEST CORPORATION 9638 PORTLAND OR
— 503-623 not yet reported which blocks → QWEST CORPORATION 9638 DALLAS OR
— 503-635 not yet reported which blocks → QWEST CORPORATION 9638 CLACKAMAS OR
— 503-636 not yet reported which blocks → QWEST CORPORATION 9638 CLACKAMAS OR
— 503-647 3XXX4XXX6XXX8XXX which blocks → QWEST CORPORATION 9638 NORTH PL OR
— 503-650 not yet reported which blocks → QWEST CORPORATION 9638 CLACKAMAS OR
— 503-652 not yet reported which blocks → QWEST CORPORATION 9638 CLACKAMAS 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.