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 623
QWEST CORPORATION 97
T-MOBILE USA, INC. 39
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 31
ONVOY, LLC - AZ 29
NEW CINGULAR WIRELESS PCS, LLC 22
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
— 623-584 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-587 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-594 not yet reported which blocks → COMCAST IP PHONE, LLC 318J PHOENIX AZ
— 623-606 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 PHOENIX AZ
— 623-611 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX AZ
— 623-628 not yet reported which blocks → T-MOBILE USA, INC. 6529 PHOENIX AZ
— 623-640 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 PHOENIX AZ
— 623-643 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-670 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 2 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 PHOENIX AZ
— 623-680 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 PHOENIX AZ
— 623-683 0–9 XXXwhole prefix which blocks → COMCAST IP PHONE, LLC 318J PHOENIX AZ
— 623-687 0XXX1XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 PHOENIX AZ
— 623-688 0XXX1XXX2XXX3XXX5XXX8XXX which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 PHOENIX AZ
— 623-691 7XXX8XXX which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-694 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 PHOENIX AZ
— 623-695 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 PHOENIX AZ
— 623-700 not yet reported which blocks → AZ
— 623-703 5XXX8XXX which blocks → T-MOBILE USA, INC. 6529 PHOENIX AZ
— 623-707 3XXX5XXX6XXX7XXX8XXX9XXX which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - AZ 7217 PHOENIX AZ
— 623-711 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX AZ
— 623-734 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 PHOENIX AZ
— 623-742 1XXX2XXX3XXX5XXX8XXX · 2 holders which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-760 2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - AZ 7217 PHOENIX AZ
— 623-764 9XXX which blocks → METROPCS, INC. 5562 PHOENIX AZ
— 623-772 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-773 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-776 5XXX6XXX which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-780 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-792 0XXX3XXX4XXX5XXX7XXX8XXX · 3 holders which blocks → LEVEL 3 TELECOM OF ARIZONA, LLC - AZ 7552 PHOENIX AZ
— 623-810 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - AZ 6572 PHOENIX AZ
— 623-811 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX AZ
— 623-815 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-824 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 3 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - AZ 7217 PHOENIX AZ
— 623-825 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-842 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-845 2XXX which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-846 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-847 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-848 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-849 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-850 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 5 holders which blocks → ELECTRIC LIGHTWAVE LLC DBA ALLSTREAM 7175 PHOENIX AZ
— 623-853 3XXX5XXX6XXX7XXX · 2 holders which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-856 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-866 2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-869 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-872 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-873 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-875 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-877 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-878 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX 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.