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 520
QWEST CORPORATION 201
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
— 520-744 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-745 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-746 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-747 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-748 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-749 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-750 3XXX which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-751 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-760 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-761 not yet reported which blocks → QWEST CORPORATION 9636 NOGALES AZ
— 520-762 2XXX4XXX6XXX7XXX · 2 holders which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-770 6XXX which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-784 1XXX3XXX4XXX8XXX9XXX which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-790 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-791 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-792 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-793 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-794 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-795 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-797 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-798 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-799 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-803 not yet reported which blocks → QWEST CORPORATION 9636 SIERRAVIST AZ
— 520-805 7XXX which blocks → QWEST CORPORATION 9636 DOUGLAS AZ
— 520-806 none assigned yet which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-807 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-818 4XXX8XXX which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-822 4XXX6XXX7XXX8XXX · 3 holders which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-825 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-836 not yet reported which blocks → QWEST CORPORATION 9636 CASAGRANDE AZ
— 520-868 not yet reported which blocks → QWEST CORPORATION 9636 CASAGRANDE AZ
— 520-872 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-873 7XXX8XXX9XXX · 3 holders which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-874 0–9 XXXwhole prefix which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-876 not yet reported which blocks → QWEST CORPORATION 9636 CASAGRANDE AZ
— 520-877 none assigned yet which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-878 3XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-879 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-880 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-881 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-882 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-883 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-884 none assigned yet which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-885 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-886 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-887 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-888 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-889 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-896 1XXX4XXX5XXX7XXX8XXX · 3 holders which blocks → QWEST CORPORATION 9636 SAN MANUEL AZ
— 520-903 4XXX7XXX8XXX which blocks → QWEST CORPORATION 9636 TUCSON AZ

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.