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 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
— 510-656 not yet reported which blocks → PACIFIC BELL 9740 FRNK OLIVR CA
— 510-657 not yet reported which blocks → PACIFIC BELL 9740 FRNK OLIVR CA
— 510-658 not yet reported which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-659 none assigned yet which blocks → PACIFIC BELL 9740 FRNK OLIVR CA
— 510-661 2XXX3XXX · 2 holders which blocks → PACIFIC BELL 9740 FRNK OLIVR CA
— 510-662 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX · 5 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 ELSBR-PINL CA
— 510-663 not yet reported which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-664 not yet reported which blocks → PACIFIC BELL 9740 OKLD BKLY CA
— 510-665 9XXX which blocks → PACIFIC BELL 9740 OKLD BKLY CA
— 510-666 4XXX5XXX6XXX7XXX · 4 holders which blocks → PACIFIC BELL 9740 OKLD BKLY CA
— 510-667 2XXX which blocks → PACIFIC BELL 9740 OKLD TRNID CA
— 510-668 9XXX which blocks → PACIFIC BELL 9740 FRNK OLIVR CA
— 510-669 5XXX which blocks → PACIFIC BELL 9740 ELSBR-PINL CA
— 510-670 not yet reported which blocks → PACIFIC BELL 9740 HAYWARD CA
— 510-673 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 FRNK MAIN CA
— 510-675 7XXX8XXX · 2 holders which blocks → PACIFIC BELL 9740 FRNK GRNLF CA
— 510-678 not yet reported which blocks → PACIFIC BELL 9740 OKLD TRNID CA
— 510-681 0XXX2XXX which blocks → METROPCS, INC. 5562 OKLD MN-PD CA
— 510-682 0XXX1XXX2XXX · 3 holders which blocks → METROPCS, INC. 5562 OKLD ALMD CA
— 510-683 1XXX5XXX · 2 holders which blocks → PACIFIC BELL 9740 FRNK OLIVR CA
— 510-684 none assigned yet which blocks → METROPCS, INC. 5562 OKLD BKLY CA
— 510-685 not yet reported which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 RICHMOND CA
— 510-686 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 7 holders which blocks → AT&T ENTERPRISES, LLC 516C OKLD TRNID CA
— 510-687 not yet reported which blocks → PACIFIC BELL 9740 FRNK OLIVR CA
— 510-688 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 HAYWARD CA
— 510-690 3XXX4XXX5XXX7XXX8XXX · 4 holders which blocks → PACIFIC BELL 9740 HAYWARD CA
— 510-692 0–9 XXXall 10 · 3 holders which blocks → METROPCS, INC. 5562 OKLD TRNID CA
— 510-693 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 OKLD MN-PD CA
— 510-697 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 OKLD MN-PD CA
— 510-698 1XXX2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 5 holders which blocks → U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 671J OKLD FRTVL CA
— 510-699 not yet reported which blocks → 33 WIRELESS INC. 6967 OKLD MN-PD CA
— 510-700 not yet reported which blocks → CA
— 510-701 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 OKLD MN-PD CA
— 510-702 not yet reported which blocks → SPOK, INC. 6630 OKLD MN-PD CA
— 510-703 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 OKLD MN-PD CA
— 510-704 3XXX which blocks → PACIFIC BELL 9740 OKLD BKLY CA
— 510-705 0XXX1XXX2XXX3XXX · 3 holders which blocks → PACIFIC BELL 9740 OKLD BKLY CA
— 510-708 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 OKLD MN-PD CA
— 510-709 0XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → IP HORIZON LLC 515J FRNK MAIN CA
— 510-710 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 OKLD MN-PD CA
— 510-711 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX CA
— 510-712 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 OKLD MN-PD CA
— 510-713 not yet reported which blocks → PACIFIC BELL 9740 FRNK MAIN CA
— 510-714 1XXX2XXX3XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 FRNK MAIN CA
— 510-715 none assigned yet which blocks → METROPCS, INC. 5562 OKLD MN-PD CA
— 510-716 not yet reported which blocks → SPOK, INC. 6630 OKLD MN-PD CA
— 510-718 not yet reported which blocks → AMERICAN MESSAGING SERVICES, LLC 9748 OKLD MN-PD CA
— 510-719 none assigned yet which blocks → METROPCS, INC. 5562 OKLD MN-PD CA
— 510-720 not yet reported which blocks → SPOK, INC. 6630 OKLD MN-PD CA
— 510-722 2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E CROCKETT 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.