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
— 510-911 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX CA
— 510-912 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 OKLD MN-PD CA
— 510-913 9XXX which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 OKLD MN-PD CA
— 510-914 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 OKLD MN-PD CA
— 510-915 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 OKLD MN-PD CA
— 510-917 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 OKLD MN-PD CA
— 510-918 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 OKLD MN-PD CA
— 510-919 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 OKLD MN-PD CA
— 510-921 0XXX1XXX2XXX4XXX6XXX7XXX8XXX9XXX which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - CA 7145 HAYWARD CA
— 510-922 0XXX1XXX8XXX9XXX · 2 holders which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-923 not yet reported which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-924 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX · 8 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 OKLD TRNID CA
— 510-926 0–9 XXXall 10 · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 OKLD BKLY CA
— 510-927 0XXX1XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 OKLD FRTVL CA
— 510-928 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 OKLD MN-PD CA
— 510-931 0XXX3XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 HAYWARD CA
— 510-936 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → PACIFIC BELL 9740 FRNK MAIN CA
— 510-940 3XXX5XXX6XXX8XXX9XXX · 4 holders which blocks → U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 671J HAYWARD CA
— 510-943 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 FRNK MAIN CA
— 510-947 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLC - CA 649C OKLD MN-PD CA
— 510-950 not yet reported which blocks → CA
— 510-953 0–9 XXXall 10 · 5 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 FRNK MAIN CA
— 510-957 3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 OKLD TRNID CA
— 510-958 not yet reported which blocks → CA
— 510-959 not yet reported which blocks → CA
— 510-960 0–9 XXXall 10 · 4 holders which blocks → AT&T - LOCAL 7421 OKLD BKLY CA
— 510-962 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 HAYWARD CA
— 510-964 2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → PACIFIC BELL 9740 ELSBR-PINL CA
— 510-965 2XXX3XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → PACIFIC BELL 9740 RICHMOND CA
— 510-967 none assigned yet which blocks → METROPCS, INC. 5562 OKLD FRTVL CA
— 510-968 not yet reported which blocks → AMERICAN MESSAGING SERVICES, LLC 9748 FRNK MAIN CA
— 510-969 0XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 OKLD TRNID CA
— 510-970 not yet reported which blocks → PACIFIC BELL 9740 RICHMOND CA
— 510-972 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → COMCAST PHONE OF CALIFORNIA, LLC 394L FRNK GRNLF CA
— 510-978 0–9 XXXall 10 · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 OKLD ALMD CA
— 510-979 2XXX which blocks → PACIFIC BELL 9740 FRNK OLIVR CA
— 510-981 9XXX which blocks → PACIFIC BELL 9740 OKLD BKLY CA
— 510-982 1XXX2XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CA 7240 OKLD BKLY CA
— 510-984 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 OKLD BKLY CA
— 510-985 4XXX9XXX which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-986 4XXX which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-987 5XXX6XXX8XXX · 3 holders which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-989 0–9 XXXall 10 · 5 holders which blocks → INTEGRATED PATH COMMUNICATIONS, LLC - CA 707H OKLD BKLY CA
— 510-990 0–9 XXXall 10 · 7 holders which blocks → ONVOY, LLC - CA 649C OKLD BKLY CA
— 510-991 6XXX7XXX which blocks → ONVOY, LLC - CA 649C FRNK GRNLF CA
— 510-992 0XXX1XXX3XXX4XXX5XXX6XXX8XXX9XXX · 6 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E OKLD MN-PD CA
— 510-995 0XXX6XXX7XXX8XXX · 3 holders which blocks → U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 671J OKLD ALMD CA
— 510-996 0XXX1XXX2XXX6XXX8XXX9XXX · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 FRNK MAIN CA
— 510-997 not yet reported which blocks → AMERICAN MESSAGING SERVICES, LLC 6906 OKLD MN-PD CA
— 510-999 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLC - CA 649C HAYWARD 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.