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
— 510-588 0XXX6XXX8XXX9XXX · 2 holders which blocks → ONVOY, LLC - CA 649C OKLD MN-PD CA
— 510-589 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 HAYWARD CA
— 510-590 3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 OKLD MN-PD CA
— 510-592 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 HRCUL-RODE CA
— 510-593 2XXX which blocks → METROPCS, INC. 5562 OKLD MN-PD CA
— 510-594 not yet reported which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-595 not yet reported which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-596 5XXX which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-597 2XXX which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-599 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 OKLD MN-PD CA
— 510-600 0–9 XXXall 10 · 5 holders which blocks → ONVOY, LLC - CA 649C HAYWARD CA
— 510-601 2XXX which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-604 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 OKLD MN-PD CA
— 510-608 2XXX which blocks → PACIFIC BELL 9740 FRNK MAIN CA
— 510-610 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 OKLD MN-PD CA
— 510-611 not yet reported which blocks → MULTIPLE OCN LISTING MULT XXXXXXXXXX CA
— 510-612 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 OKLD MN-PD CA
— 510-613 3XXX4XXX5XXX · 2 holders which blocks → PACIFIC BELL 9740 OKLD TRNID CA
— 510-614 not yet reported which blocks → PACIFIC BELL 9740 OKLD TRNID CA
— 510-615 not yet reported which blocks → PACIFIC BELL 9740 OKLD TRNID CA
— 510-618 9XXX which blocks → PACIFIC BELL 9740 OKLD TRNID CA
— 510-619 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 RICHMOND CA
— 510-620 4XXX which blocks → PACIFIC BELL 9740 RICHMOND CA
— 510-621 3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 RICHMOND CA
— 510-622 not yet reported which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-623 4XXX which blocks → PACIFIC BELL 9740 FRNK OLIVR CA
— 510-624 1XXX9XXX · 2 holders which blocks → PACIFIC BELL 9740 FRNK OLIVR CA
— 510-625 not yet reported which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-627 9XXX which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-628 6XXX which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-629 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 OKLD ALMD CA
— 510-632 not yet reported which blocks → PACIFIC BELL 9740 OKLD TRNID CA
— 510-633 not yet reported which blocks → PACIFIC BELL 9740 OKLD TRNID CA
— 510-635 not yet reported which blocks → PACIFIC BELL 9740 OKLD TRNID CA
— 510-636 5XXX6XXX · 2 holders which blocks → PACIFIC BELL 9740 OKLD TRNID CA
— 510-637 7XXX8XXX9XXX · 2 holders which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-638 not yet reported which blocks → PACIFIC BELL 9740 OKLD TRNID CA
— 510-639 not yet reported which blocks → PACIFIC BELL 9740 OKLD TRNID CA
— 510-642 not yet reported which blocks → PACIFIC BELL 9740 OKLD BKLY CA
— 510-643 not yet reported which blocks → PACIFIC BELL 9740 OKLD BKLY CA
— 510-644 not yet reported which blocks → PACIFIC BELL 9740 OKLD BKLY CA
— 510-645 not yet reported which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-647 6XXX7XXX8XXX9XXX · 3 holders which blocks → PACIFIC BELL 9740 OKLD BKLY CA
— 510-648 2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 FRNK MAIN CA
— 510-649 not yet reported which blocks → PACIFIC BELL 9740 OKLD BKLY CA
— 510-651 not yet reported which blocks → PACIFIC BELL 9740 FRNK OLIVR CA
— 510-652 not yet reported which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-653 not yet reported which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-654 not yet reported which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-655 not yet reported which blocks → PACIFIC BELL 9740 OKLD MN-PD 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.