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
2015-02-03 323-561 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 03 CA
2014-12-23 323-738 0–9 XXXwhole prefix which blocks → METROPCS NETWORKS, LLC 899D LSAN DA 13 CA
2014-12-23 323-891 0–9 XXXall 10 · 2 holders which blocks → METROPCS NETWORKS, LLC 899D LSAN DA 14 CA
2014-12-22 323-670 0–9 XXXwhole prefix which blocks → METROPCS NETWORKS, LLC 899D MONTEBELLO CA
2014-12-22 323-827 0–9 XXXall 10 · 4 holders which blocks → METROPCS NETWORKS, LLC 899D MONTEBELLO CA
2014-12-08 323-593 0–9 XXXall 10 · 5 holders which blocks → METROPCS NETWORKS, LLC 899D LSAN DA 02 CA
2014-11-24 323-598 0–9 XXXwhole prefix which blocks → METROPCS NETWORKS, LLC 899D MONTEBELLO CA
2014-11-24 323-676 0–9 XXXall 10 · 5 holders which blocks → ONVOY, LLC - CA 649C LSAN DA 08 CA
2014-11-24 323-894 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - CA 649C LSAN DA 06 CA
2014-11-04 323-631 0–9 XXXwhole prefix which blocks → METROPCS NETWORKS, LLC 899D MONTEBELLO CA
2014-10-30 323-886 0–9 XXXwhole prefix which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E LSAN DA 06 CA
2014-10-17 323-597 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 MONTEBELLO CA
2014-10-16 323-672 0–9 XXXall 10 · 5 holders which blocks → METROPCS NETWORKS, LLC 899D LSAN DA 14 CA
2014-10-14 323-884 0–9 XXXwhole prefix which blocks → METROPCS NETWORKS, LLC 899D MONTEBELLO CA
2014-09-22 323-548 0–9 XXXwhole prefix which blocks → METROPCS NETWORKS, LLC 899D MONTEBELLO CA
2014-09-09 323-797 0–9 XXXall 10 · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 MONTEBELLO CA
2014-09-08 323-688 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 14 CA
2014-07-25 323-553 0–9 XXXall 10 · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E LSAN DA 06 CA
2014-06-06 323-746 0–9 XXXall 10 · 6 holders which blocks → AT&T ENTERPRISES, LLC 516C LSAN DA 13 CA
2014-05-02 323-745 0–9 XXXall 10 · 5 holders which blocks → ONVOY, LLC - CA 649C LSAN DA 14 CA
2014-03-04 323-741 0–9 XXXall 10 · 5 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CA 7240 LSAN DA 02 CA
2014-02-28 323-694 0–9 XXXall 10 · 5 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E LSAN DA 02 CA
2014-02-28 323-736 0–9 XXXall 10 · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E LSAN DA 14 CA
2014-01-27 323-621 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 MONTEBELLO CA
2013-12-19 323-457 0–9 XXXall 10 · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 LSAN DA 06 CA
2013-12-13 323-673 0–9 XXXall 10 · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E LSAN DA 03 CA
2013-08-02 323-489 0–9 XXXall 10 · 4 holders which blocks → METROPCS NETWORKS, LLC 899D LSAN DA 02 CA
2013-07-15 323-714 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 MONTEBELLO CA
2013-06-13 323-484 0–9 XXXall 10 · 3 holders which blocks → TWC IP ENABLED SERVICES, LLC 793K LSAN DA 06 CA
2013-06-13 323-536 0–9 XXXall 10 · 5 holders which blocks → TWC IP ENABLED SERVICES, LLC 793K LSAN DA 14 CA
2013-03-05 323-591 0–9 XXXall 10 · 6 holders which blocks → TWC IP ENABLED SERVICES, LLC 793K LSAN DA 13 CA
2013-02-27 323-430 0–9 XXXall 10 · 5 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 MONTEBELLO CA
2013-02-14 323-531 0–9 XXXall 10 · 6 holders which blocks → TWC IP ENABLED SERVICES, LLC 793K LSAN DA 09 CA
2013-02-11 323-538 0–9 XXXall 10 · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E LSAN DA 06 CA
2013-02-01 323-498 0–9 XXXall 10 · 7 holders which blocks → CENTURYLINK COMMUNICATIONS, LLC 508J LSAN DA 14 CA
2013-01-14 323-453 0–9 XXXall 10 · 2 holders which blocks → METROPCS NETWORKS, LLC 899D MONTEBELLO CA
2012-12-03 323-486 0–9 XXXall 10 · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E LSAN DA 02 CA
2012-11-21 323-437 0–9 XXXall 10 · 2 holders which blocks → METROPCS NETWORKS, LLC 899D MONTEBELLO CA
2012-11-07 323-487 0–9 XXXall 10 · 5 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E LSAN DA 06 CA
2012-10-01 323-483 0–9 XXXall 10 · 4 holders which blocks → METROPCS NETWORKS, LLC 899D MONTEBELLO CA
2012-08-13 323-480 0–9 XXXall 10 · 5 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 MONTEBELLO CA
2012-07-13 323-477 0–9 XXXall 10 · 5 holders which blocks → METROPCS NETWORKS, LLC 899D MONTEBELLO CA
2012-05-30 323-452 0–9 XXXall 10 · 4 holders which blocks → TWC IP ENABLED SERVICES, LLC 793K LSAN DA 13 CA
2012-04-16 323-416 0–9 XXXwhole prefix which blocks → PEERLESS NETWORK OF CALIFORNIA, LLC - CA 373F MONTEBELLO CA
2012-03-02 323-458 0–9 XXXall 10 · 4 holders which blocks → METROPCS NETWORKS, LLC 899D MONTEBELLO CA
2011-12-23 323-358 0–9 XXXall 10 · 3 holders which blocks → METROPCS NETWORKS, LLC 899D MONTEBELLO CA
2011-11-21 323-438 0–9 XXXall 10 · 2 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E LSAN DA 06 CA
2011-07-01 323-435 0–9 XXXall 10 · 2 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E LSAN DA 06 CA
2011-06-29 323-426 0–9 XXXall 10 · 4 holders which blocks → METROPCS NETWORKS, LLC 899D LSAN DA 02 CA
2011-06-08 323-976 not yet reported which blocks → NORTH COUNTY COMMUNICATION CORPORATION - CA 7894 LSAN DA 14 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.