NumberResearch Membership · Data 10/01/2026

Recent prefix assignments

374 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 10/01/2026

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, last 30 days
Rogers Communications Canada Inc. (Wireless) 46
8X8, INC. 43
NEW CINGULAR WIRELESS PCS, LLC - DC 28
NEW CINGULAR WIRELESS PCS, LLC - IL 23
ONVOY, LLC - CA 19
New assignments by month Oct 2026 Sep 2026 Aug 2026 Jul 2026 Jun 2026 May 2026 Apr 2026 Mar 2026 Feb 2026 Jan 2026 Dec 2025 Nov 2025
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Recent NPA-NXX prefix assignments
AssignedNPA-NXXThousands-blocks taken (last-4 opening)Code holderOCNRate centerState
— 510-531 not yet reported which blocks → PACIFIC BELL 9740 OKLD FRTVL CA
— 510-532 not yet reported which blocks → PACIFIC BELL 9740 OKLD FRTVL CA
— 510-533 not yet reported which blocks → PACIFIC BELL 9740 OKLD FRTVL CA
— 510-534 not yet reported which blocks → PACIFIC BELL 9740 OKLD FRTVL CA
— 510-535 not yet reported which blocks → PACIFIC BELL 9740 OKLD FRTVL CA
— 510-536 not yet reported which blocks → PACIFIC BELL 9740 OKLD FRTVL CA
— 510-537 not yet reported which blocks → PACIFIC BELL 9740 HAYWARD CA
— 510-538 not yet reported which blocks → PACIFIC BELL 9740 HAYWARD CA
— 510-539 not yet reported which blocks → UTILITY TELECOM GROUP, LLC - CA 9262 OKLD MN-PD CA
— 510-540 not yet reported which blocks → PACIFIC BELL 9740 OKLD BKLY CA
— 510-541 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 OKLD MN-PD CA
— 510-542 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 OKLD BKLY CA
— 510-543 0XXX1XXX2XXX · 2 holders which blocks → METROPCS, INC. 5562 OKLD MN-PD CA
— 510-544 1XXX9XXX · 2 holders which blocks → ONVOY, LLC - CA 649C OKLD TRNID CA
— 510-545 2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 OKLD ALMD CA
— 510-547 not yet reported which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-548 not yet reported which blocks → PACIFIC BELL 9740 OKLD BKLY CA
— 510-549 6XXX7XXX · 2 holders which blocks → PACIFIC BELL 9740 OKLD BKLY CA
— 510-550 0XXX5XXX6XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 OKLD MN-PD CA
— 510-551 9XXX which blocks → METROPCS, INC. 5562 OKLD MN-PD CA
— 510-553 not yet reported which blocks → PACIFIC BELL 9740 OKLD TRNID CA
— 510-554 not yet reported which blocks → 33 WIRELESS INC. 6967 HAYWARD CA
— 510-555 not yet reported which blocks → MULTIPLE OCN LISTING MULT DIR ASST CA
— 510-558 5XXX which blocks → PACIFIC BELL 9740 OKLD BKLY CA
— 510-559 0XXX which blocks → PACIFIC BELL 9740 OKLD BKLY CA
— 510-562 not yet reported which blocks → PACIFIC BELL 9740 OKLD TRNID CA
— 510-563 0XXX7XXX9XXX · 2 holders which blocks → PACIFIC BELL 9740 OKLD TRNID CA
— 510-564 2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 OKLD TRNID CA
— 510-565 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 FRNK MAIN CA
— 510-566 0–9 XXXall 10 · 2 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 HAYWARD CA
— 510-567 3XXX4XXX7XXX · 3 holders which blocks → PACIFIC BELL 9740 OKLD TRNID CA
— 510-568 not yet reported which blocks → PACIFIC BELL 9740 OKLD TRNID CA
— 510-569 not yet reported which blocks → PACIFIC BELL 9740 OKLD TRNID CA
— 510-572 not yet reported which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CA 7240 FRNK OLIVR CA
— 510-573 5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → COMCAST PHONE OF CALIFORNIA, LLC 394L FRNK OLIVR CA
— 510-574 5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → PACIFIC BELL 9740 FRNK MAIN CA
— 510-575 0–9 XXXall 10 · 2 holders which blocks → METROPCS, INC. 5562 OKLD MN-PD CA
— 510-576 3XXX4XXX5XXX8XXX9XXX · 4 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 HAYWARD CA
— 510-577 not yet reported which blocks → PACIFIC BELL 9740 OKLD TRNID CA
— 510-578 4XXX6XXX7XXX8XXX · 3 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 FRNK MAIN CA
— 510-579 not yet reported which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 FRNK MAIN CA
— 510-580 not yet reported which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 FRNK OLIVR CA
— 510-581 not yet reported which blocks → PACIFIC BELL 9740 HAYWARD CA
— 510-582 not yet reported which blocks → PACIFIC BELL 9740 HAYWARD CA
— 510-583 not yet reported which blocks → PACIFIC BELL 9740 HAYWARD CA
— 510-584 1XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 HAYWARD CA
— 510-585 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 671J FRNK MAIN CA
— 510-586 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → COMCAST PHONE OF CALIFORNIA, LLC 394L HAYWARD CA
— 510-587 9XXX which blocks → PACIFIC BELL 9740 OKLD MN-PD CA
— 510-588 0XXX6XXX8XXX9XXX · 2 holders which blocks → ONVOY, LLC - CA 649C OKLD MN-PD CA

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 10/01/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.