NumberResearch Membership · Data 09/20/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/20/2026

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 323
PACIFIC BELL 265
METROPCS NETWORKS, LLC 85
T-MOBILE USA, INC. 64
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 45
NEW CINGULAR WIRELESS PCS, LLC 39
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
— 323-478 none assigned yet which blocks → PACIFIC BELL 9740 LSAN DA 03 CA
— 323-488 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E LSAN DA 05 CA
— 323-491 0XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - CA 7139 LSAN DA 14 CA
— 323-492 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 LSAN DA 09 CA
— 323-493 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 LSAN DA 14 CA
— 323-495 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 02 CA
— 323-496 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 LSAN DA 06 CA
— 323-497 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 LSAN DA 14 CA
— 323-499 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 14 CA
— 323-500 0XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 MONTEBELLO CA
— 323-502 not yet reported which blocks → SPOK, INC. 6630 LSAN DA 09 CA
— 323-503 0XXX3XXX5XXX6XXX7XXX8XXX9XXX which blocks → IP HORIZON LLC 515J LSAN DA 02 CA
— 323-504 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 14 CA
— 323-505 1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 671J LSAN DA 04 CA
— 323-507 0–9 XXXall 10 · 4 holders which blocks → PEERLESS NETWORK OF CALIFORNIA, LLC - CA 373F LSAN DA 03 CA
— 323-508 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 671J LSAN DA 12 CA
— 323-509 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 03 CA
— 323-510 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 LSAN DA 05 CA
— 323-511 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX CA
— 323-512 1XXX9XXX · 2 holders which blocks → PACIFIC BELL 9740 LSAN DA 14 CA
— 323-515 0–9 XXXall 10 · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 LSAN DA 08 CA
— 323-516 0–9 XXXall 10 · 5 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 MONTEBELLO CA
— 323-517 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 2 holders which blocks → PAETEC ITEL, LLC 829J MONTEBELLO CA
— 323-520 not yet reported which blocks → PACIFIC BELL 9740 LSAN DA 14 CA
— 323-521 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → PACIFIC BELL 9740 LSAN DA 08 CA
— 323-522 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 671J LSAN DA 02 CA
— 323-523 1XXX3XXX4XXX5XXX6XXX7XXX9XXX · 3 holders which blocks → U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 671J LSAN DA 06 CA
— 323-525 not yet reported which blocks → PACIFIC BELL 9740 LSAN DA 13 CA
— 323-526 8XXX which blocks → PACIFIC BELL 9740 LSAN DA 05 CA
— 323-528 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 LSAN DA 09 CA
— 323-533 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 LSAN DA 14 CA
— 323-535 0–9 XXXwhole prefix which blocks → U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 671J LSAN DA 02 CA
— 323-539 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → PACIFIC BELL 9740 LSAN DA 04 CA
— 323-540 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 03 CA
— 323-541 2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → PACIFIC BELL 9740 LSAN DA 09 CA
— 323-543 0XXX1XXX3XXX4XXX5XXX6XXX7XXX · 3 holders which blocks → U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 671J LSAN DA 03 CA
— 323-544 3XXX5XXX7XXX8XXX · 2 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 LSAN DA 08 CA
— 323-545 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → PACIFIC BELL 9740 LSAN DA 12 CA
— 323-546 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 LSAN DA 08 CA
— 323-547 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 LSAN DA 09 CA
— 323-549 8XXX which blocks → PACIFIC BELL 9740 LSAN DA 13 CA
— 323-550 not yet reported which blocks → PACIFIC BELL 9740 LSAN DA 03 CA
— 323-551 7XXX8XXX9XXX · 2 holders which blocks → PACIFIC BELL 9740 LSAN DA 03 CA
— 323-552 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 LSAN DA 09 CA
— 323-555 not yet reported which blocks → MULTIPLE OCN LISTING MULT DIR ASST CA
— 323-556 1XXX4XXX which blocks → U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 671J LSAN DA 13 CA
— 323-557 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 LSAN DA 13 CA
— 323-558 1XXX2XXX3XXX4XXX6XXX8XXX9XXX · 3 holders which blocks → U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 671J MONTEBELLO CA
— 323-559 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 LSAN DA 06 CA
— 323-560 not yet reported which blocks → PACIFIC BELL 9740 LSAN DA 06 CA

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/20/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.