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
2016-12-09 510-826 0–9 XXXall 10 · 5 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 HAYWARD CA
2016-10-21 510-822 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 OKLD TRNID CA
2016-09-26 510-570 0–9 XXXall 10 · 7 holders which blocks → T-MOBILE USA, INC. 6529 OKLD BKLY CA
2016-09-19 510-514 0–9 XXXall 10 · 4 holders which blocks → PEERLESS NETWORK OF CALIFORNIA, LLC - CA 373F HAYWARD CA
2016-08-30 510-513 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 FRNK MAIN CA
2016-08-26 510-738 0–9 XXXall 10 · 6 holders which blocks → PEERLESS NETWORK OF CALIFORNIA, LLC - CA 373F FRNK OLIVR CA
2016-08-25 510-726 0–9 XXXall 10 · 5 holders which blocks → PEERLESS NETWORK OF CALIFORNIA, LLC - CA 373F CROCKETT CA
2016-07-29 510-424 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 OKLD FRTVL CA
2016-07-29 510-626 0–9 XXXall 10 · 6 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E OKLD TRNID CA
2016-07-29 510-901 0–9 XXXall 10 · 6 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E HAYWARD CA
2016-07-15 510-906 0–9 XXXall 10 · 6 holders which blocks → ONVOY, LLC - CA 649C OKLD ALMD CA
2016-07-15 510-949 0–9 XXXall 10 · 6 holders which blocks → ONVOY, LLC - CA 649C HRCUL-RODE CA
2016-06-14 510-890 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 RICHMOND CA
2016-06-10 510-993 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 OKLD BKLY CA
2016-06-09 510-806 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 RICHMOND CA
2016-05-06 510-399 0–9 XXXall 10 · 6 holders which blocks → ONVOY, LLC - CA 649C FRNK MAIN CA
2016-05-04 510-462 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - CA 649C FRNK GRNLF CA
2016-04-01 510-707 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 OKLD TRNID CA
2016-02-04 510-369 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLC - CA 649C RICHMOND CA
2016-01-15 510-345 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 OKLD BKLY CA
2015-12-28 510-330 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLC - CA 649C HAYWARD CA
2015-12-01 510-319 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - CA 649C FRNK OLIVR CA
2015-11-13 510-737 0–9 XXXall 10 · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 FRNK MAIN CA
2015-11-13 510-963 0–9 XXXall 10 · 5 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 HAYWARD CA
2015-10-02 510-631 0–9 XXXall 10 · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 OKLD BKLY CA
2015-09-25 510-422 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 OKLD FRTVL CA
2015-09-22 510-203 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 FRNK MAIN CA
2015-09-22 510-241 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 ELSBR-PINL CA
2015-09-09 510-756 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 OKLD TRNID CA
2015-08-11 510-660 0–9 XXXall 10 · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 RICHMOND CA
2015-07-10 510-820 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 OKLD TRNID CA
2015-06-22 510-696 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 OKLD FRTVL CA
2015-06-11 510-946 0–9 XXXall 10 · 5 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 FRNK OLIVR CA
2015-06-09 510-937 0–9 XXXall 10 · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E CROCKETT CA
2015-05-01 510-640 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 ELSBR-PINL CA
2015-04-13 510-679 0–9 XXXall 10 · 5 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 OKLD BKLY CA
2015-04-13 510-850 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 OKLD TRNID CA
2015-04-10 510-945 0–9 XXXall 10 · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 FRNK GRNLF CA
2015-03-25 510-766 0–9 XXXall 10 · 5 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E FRNK MAIN CA
2015-03-25 510-939 0–9 XXXall 10 · 5 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E HRCUL-RODE CA
2015-03-11 510-934 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 OKLD FRTVL CA
2014-12-08 510-694 0–9 XXXall 10 · 3 holders which blocks → ONVOY, LLC - CA 649C OKLD ALMD CA
2014-12-01 510-942 0–9 XXXall 10 · 5 holders which blocks → TELEPORT COMMUNICATIONS AMERICA, LLC - CA 7145 RICHMOND CA
2014-11-25 510-753 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 OKLD TRNID CA
2014-11-03 510-674 0–9 XXXall 10 · 4 holders which blocks → ONVOY, LLC - CA 649C HAYWARD CA
2014-10-27 510-361 0–9 XXXall 10 · 6 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 HAYWARD CA
2014-10-24 510-309 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 ELSBR-PINL CA
2014-10-14 510-458 0–9 XXXall 10 · 3 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 FRNK MAIN CA
2014-10-03 510-944 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 OKLD BKLY CA
2014-09-24 510-634 0–9 XXXall 10 · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 HAYWARD 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.