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 510
PACIFIC BELL 278
NEW CINGULAR WIRELESS PCS, LLC 78
T-MOBILE USA, INC. 65
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 60
METROPCS, INC. 45
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
— 510-405 not yet reported which blocks → ONVOY, LLC - CA 649C FRNK MAIN CA
— 510-406 7XXX which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 OKLD MN-PD CA
— 510-407 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 OKLD MN-PD CA
— 510-409 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 OKLD MN-PD CA
— 510-410 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 OKLD MN-PD CA
— 510-411 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX CA
— 510-412 not yet reported which blocks → PACIFIC BELL 9740 RICHMOND CA
— 510-413 2XXX3XXX6XXX7XXX8XXX · 4 holders which blocks → PACIFIC BELL 9740 FRNK OLIVR CA
— 510-414 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 OKLD MN-PD CA
— 510-416 not yet reported which blocks → NORTH COUNTY COMMUNICATION CORPORATION - CA 7894 OKLD BKLY CA
— 510-418 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 OKLD MN-PD CA
— 510-419 7XXX9XXX · 2 holders which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-420 not yet reported which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-421 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 OKLD MN-PD CA
— 510-425 none assigned yet which blocks → PACIFIC BELL 9740 OKLD TRNID CA
— 510-427 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 HAYWARD CA
— 510-428 not yet reported which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-429 not yet reported which blocks → PACIFIC BELL 9740 FRNK GRNLF CA
— 510-430 not yet reported which blocks → PACIFIC BELL 9740 OKLD TRNID CA
— 510-431 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 FRNK GRNLF CA
— 510-433 8XXX which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-434 4XXX6XXX8XXX which blocks → PACIFIC BELL 9740 OKLD FRTVL CA
— 510-435 none assigned yet which blocks → T-MOBILE USA, INC. 6529 OKLD MN-PD CA
— 510-436 not yet reported which blocks → PACIFIC BELL 9740 OKLD FRTVL CA
— 510-437 0XXX which blocks → PACIFIC BELL 9740 OKLD FRTVL CA
— 510-438 1XXX3XXX which blocks → PACIFIC BELL 9740 FRNK OLIVR CA
— 510-439 3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → ONVOY, LLC - CA 649C RICHMOND CA
— 510-440 2XXX3XXX5XXX7XXX · 4 holders which blocks → PACIFIC BELL 9740 FRNK OLIVR CA
— 510-441 4XXX which blocks → PACIFIC BELL 9740 FRNK GRNLF CA
— 510-442 not yet reported which blocks → UTILITY TELECOM GROUP, LLC - CA 9262 OKLD MN-PD CA
— 510-444 9XXX which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-445 3XXX7XXX8XXX9XXX · 2 holders which blocks → PACIFIC BELL 9740 FRNK OLIVR CA
— 510-446 8XXX which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-448 not yet reported which blocks → UTILITY TELECOM GROUP, LLC - CA 9262 OKLD MN-PD CA
— 510-449 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - CA 7145 FRNK MAIN CA
— 510-450 not yet reported which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-451 not yet reported which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-452 7XXX which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-453 none assigned yet which blocks → METROPCS, INC. 5562 FRNK MAIN CA
— 510-456 0XXX5XXX6XXX8XXX · 2 holders which blocks → U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 671J FRNK MAIN CA
— 510-457 0XXX1XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - CA 7145 OKLD MN-PD CA
— 510-459 none assigned yet which blocks → T-MOBILE USA, INC. 6529 OKLD MN-PD CA
— 510-463 1XXX3XXX4XXX7XXX8XXX9XXX · 4 holders which blocks → U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 671J OKLD MN-PD CA
— 510-464 0XXX which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-465 not yet reported which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-466 1XXX which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-467 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 OKLD FRTVL CA
— 510-468 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 FRNK MAIN CA
— 510-469 0XXX2XXX9XXX · 3 holders which blocks → METROPCS, INC. 5562 OKLD MN-PD CA
— 510-471 not yet reported which blocks → PACIFIC BELL 9740 FRNK GRNLF CA

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.