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 520
QWEST CORPORATION 201
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 104
T-MOBILE USA, INC. 84
NEW CINGULAR WIRELESS PCS, LLC 53
ONVOY, LLC - AZ 47
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
— 520-489 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-490 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
— 520-491 none assigned yet which blocks → T-MOBILE USA, INC. 6529 FLAGSTAFF AZ
— 520-494 2XXX3XXX4XXX · 3 holders which blocks → QWEST CORPORATION 9636 CASAGRANDE AZ
— 520-495 0XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 6 holders which blocks → LEVEL 3 TELECOM OF ARIZONA, LLC - AZ 7552 TUCSON AZ
— 520-498 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-507 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 WILLCOX AZ
— 520-508 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 SIERRAVIST AZ
— 520-510 0XXX1XXX2XXX4XXX5XXX · 4 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 CASAGRANDE AZ
— 520-511 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX AZ
— 520-512 6XXX7XXX which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-513 1XXX2XXX5XXX6XXX7XXX8XXX9XXX which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-514 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-515 not yet reported which blocks → QWEST CORPORATION 9636 SIERRAVIST AZ
— 520-516 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-518 3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 CASAGRANDE AZ
— 520-519 9XXX which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-529 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-531 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-533 not yet reported which blocks → QWEST CORPORATION 9636 SIERRAVIST AZ
— 520-538 not yet reported which blocks → QWEST CORPORATION 9636 SIERRAVIST AZ
— 520-544 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-545 not yet reported which blocks → LEVEL 3 TELECOM OF ARIZONA, LLC - AZ 7552 TUCSON AZ
— 520-546 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-547 not yet reported which blocks → LEVEL 3 TELECOM OF ARIZONA, LLC - AZ 7552 TUCSON AZ
— 520-549 0XXX1XXX2XXX3XXX4XXX5XXX6XXX · 2 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
— 520-550 not yet reported which blocks → GILA RIVER TELECOMM, INC. 2179 KOMATKE AZ
— 520-552 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → ONVOY, LLC - AZ 630E BISBEE AZ
— 520-555 not yet reported which blocks → MULTIPLE OCN LISTING MULT DIR ASST AZ
— 520-558 not yet reported which blocks → VALLEY TEL COOP INC 2176 PORTAL AZ
— 520-559 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 SIERRAVIST AZ
— 520-560 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 CASAGRANDE AZ
— 520-561 5XXX6XXX7XXX8XXX · 2 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
— 520-562 not yet reported which blocks → GILA RIVER TELECOMM, INC. 2179 SACATON AZ
— 520-566 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-568 not yet reported which blocks → QWEST CORPORATION 9636 CASAGRANDE AZ
— 520-570 4XXX5XXX8XXX9XXX which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-571 3XXX5XXX · 2 holders which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-572 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-573 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-574 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-575 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-576 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-577 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-578 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-579 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-582 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 TELECOM OF ARIZONA, LLC - AZ 7552 CASAGRANDE AZ
— 520-584 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-586 not yet reported which blocks → QWEST CORPORATION 9636 BENSON AZ
— 520-591 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ

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.