NumberResearch Membership · Data 09/27/2026

Recent prefix assignments

341 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/27/2026

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, last 30 days
8X8, INC. 43
NEW CINGULAR WIRELESS PCS, LLC - DC 26
Rogers Communications Canada Inc. (Wireless) 23
NEW CINGULAR WIRELESS PCS, LLC - IL 22
ONVOY, LLC - CA 21
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
— 623-330 not yet reported which blocks → T-MOBILE USA, INC. 6529 PHOENIX AZ
— 623-332 not yet reported which blocks → T-MOBILE USA, INC. 6529 PHOENIX AZ
— 623-334 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-337 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX · 4 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - AZ 7217 PHOENIX AZ
— 623-340 none assigned yet which blocks → T-MOBILE USA, INC. 6529 PHOENIX AZ
— 623-341 none assigned yet which blocks → T-MOBILE USA, INC. 6529 PHOENIX AZ
— 623-344 9XXX which blocks → ELECTRIC LIGHTWAVE LLC DBA ALLSTREAM 7175 PHOENIX AZ
— 623-349 0XXX1XXX2XXX3XXX4XXX7XXX8XXX9XXX · 5 holders which blocks → ELECTRIC LIGHTWAVE LLC DBA ALLSTREAM 7175 PHOENIX AZ
— 623-362 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-363 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 PHOENIX AZ
— 623-374 1XXX2XXX3XXX4XXX6XXX7XXX · 2 holders which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-376 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-383 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - AZ 630E PHOENIX AZ
— 623-385 2XXX5XXX6XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 TELECOM OF ARIZONA, LLC - AZ 7552 PHOENIX AZ
— 623-386 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-388 1XXX3XXX4XXX6XXX7XXX · 3 holders which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-393 none assigned yet which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-398 4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → XO ARIZONA, INC. 4793 PHOENIX AZ
— 623-399 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 PHOENIX AZ
— 623-411 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX AZ
— 623-412 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-434 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-435 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-444 0XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - AZ 7217 PHOENIX AZ
— 623-445 1XXX which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-451 none assigned yet which blocks → T-MOBILE USA, INC. 6529 PHOENIX AZ
— 623-463 none assigned yet which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-465 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-466 0–9 XXXall 10 · 3 holders which blocks → COMCAST IP PHONE, LLC 318J PHOENIX AZ
— 623-474 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-476 2XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 PHOENIX AZ
— 623-478 2XXX which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-486 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-487 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-492 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-505 3XXX7XXX8XXX · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - AZ 3285 PHOENIX AZ
— 623-511 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX AZ
— 623-512 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX which blocks → ELECTRIC LIGHTWAVE LLC DBA ALLSTREAM 7175 PHOENIX AZ
— 623-516 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-518 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 PHOENIX AZ
— 623-521 none assigned yet which blocks → T-MOBILE USA, INC. 6529 PHOENIX AZ
— 623-523 1XXX2XXX3XXX4XXX7XXX9XXX which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-533 3XXX4XXX5XXX6XXX which blocks → T-MOBILE USA, INC. 6529 PHOENIX AZ
— 623-535 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-536 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-537 5XXX7XXX · 2 holders which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-544 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-546 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-547 5XXX6XXX7XXX9XXX · 2 holders which blocks → QWEST CORPORATION 9636 PHOENIX AZ
— 623-551 not yet reported which blocks → QWEST CORPORATION 9636 PHOENIX AZ

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/27/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.