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
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Recent NPA-NXX prefix assignments
AssignedNPA-NXXThousands-blocks taken (last-4 opening)Code holderOCNRate centerState
— 520-397 3XXX4XXX6XXX · 3 holders which blocks → QWEST CORPORATION 9636 NOGALES AZ
— 520-398 4XXX5XXX6XXX7XXX which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-399 5XXX6XXX7XXX8XXX · 2 holders which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-400 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
— 520-401 none assigned yet which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
— 520-403 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
— 520-404 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
— 520-405 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
— 520-407 5XXX6XXX which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-408 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-409 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 TUCSON AZ
— 520-410 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-411 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX AZ
— 520-417 not yet reported which blocks → QWEST CORPORATION 9636 SIERRAVIST AZ
— 520-418 not yet reported which blocks → GILA RIVER TELECOMM, INC. 2179 STOTONIC AZ
— 520-419 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
— 520-421 not yet reported which blocks → QWEST CORPORATION 9636 CASAGRANDE AZ
— 520-423 3XXX4XXX5XXX6XXX7XXX9XXX · 4 holders which blocks → QWEST CORPORATION 9636 CASAGRANDE AZ
— 520-424 1XXX2XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → QWEST CORPORATION 9636 CASAGRANDE AZ
— 520-426 not yet reported which blocks → QWEST CORPORATION 9636 CASAGRANDE AZ
— 520-429 6XXX7XXX8XXX9XXX which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
— 520-430 not yet reported which blocks → GILA RIVER TELECOMM, INC. 2179 MARCOPAVLG AZ
— 520-431 6XXX7XXX8XXX9XXX which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 CASAGRANDE AZ
— 520-432 0XXX which blocks → QWEST CORPORATION 9636 BISBEE AZ
— 520-434 1XXX which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-439 not yet reported which blocks → QWEST CORPORATION 9636 SIERRAVIST AZ
— 520-440 not yet reported which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
— 520-444 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
— 520-445 0–9 XXXall 10 · 4 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 TUCSON AZ
— 520-446 not yet reported which blocks → SPOK, INC. 6630 TUCSON AZ
— 520-449 2XXX3XXX5XXX6XXX8XXX · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
— 520-450 4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 CASAGRANDE AZ
— 520-452 not yet reported which blocks → QWEST CORPORATION 9636 SIERRAVIST AZ
— 520-455 1XXX2XXX3XXX6XXX7XXX8XXX · 4 holders which blocks → QWEST CORPORATION 9636 NOGALES AZ
— 520-456 4XXX5XXX6XXX7XXX which blocks → QWEST CORPORATION 9636 SIERRAVIST AZ
— 520-457 0XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → QWEST CORPORATION 9636 TOMBSTONE AZ
— 520-458 not yet reported which blocks → QWEST CORPORATION 9636 SIERRAVIST AZ
— 520-459 not yet reported which blocks → QWEST CORPORATION 9636 SIERRAVIST AZ
— 520-461 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → ELECTRIC LIGHTWAVE LLC DBA ALLSTREAM 7175 TUCSON AZ
— 520-463 3XXX4XXX7XXX9XXX · 4 holders which blocks → QWEST CORPORATION 9636 WHITLOW AZ
— 520-464 2XXX4XXX5XXX6XXX7XXX9XXX · 2 holders which blocks → QWEST CORPORATION 9636 CASAGRANDE AZ
— 520-465 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 TUCSON AZ
— 520-466 not yet reported which blocks → QWEST CORPORATION 9636 CASAGRANDE AZ
— 520-469 not yet reported which blocks → QWEST CORPORATION 9636 TUCSON AZ
— 520-470 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 NOGALES AZ
— 520-471 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 TUCSON AZ
— 520-481 not yet reported which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
— 520-483 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 CASAGRANDE AZ
— 520-487 1XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → QWEST CORPORATION 9636 SAN MANUEL AZ
— 520-488 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.