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
2014-09-19 510-974 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 RICHMOND CA
2014-09-18 510-925 0–9 XXXall 10 · 3 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E HAYWARD CA
2014-08-18 510-829 0–9 XXXall 10 · 3 holders which blocks → METROPCS, INC. 5562 RICHMOND CA
2014-07-28 510-833 0–9 XXXall 10 · 4 holders which blocks → COMCAST PHONE OF CALIFORNIA, LLC 394L OKLD BKLY CA
2014-07-28 510-871 0–9 XXXall 10 · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 OKLD ALMD CA
2014-07-14 510-560 0–9 XXXall 10 · 5 holders which blocks → COMCAST PHONE OF CALIFORNIA, LLC 394L OKLD TRNID CA
2014-05-05 510-556 0–9 XXXall 10 · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 FRNK MAIN CA
2014-03-27 510-426 0–9 XXXall 10 · 5 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 RICHMOND CA
2014-03-27 510-876 0–9 XXXall 10 · 6 holders which blocks → AT&T ENTERPRISES, LLC 516C HAYWARD CA
2014-03-27 510-935 0–9 XXXall 10 · 3 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 HAYWARD CA
2014-02-28 510-838 0–9 XXXall 10 · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E OKLD FRTVL CA
2013-12-09 510-736 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 HAYWARD CA
2013-09-26 510-365 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 OKLD BKLY CA
2013-09-26 510-480 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 ELSBR-PINL CA
2013-09-12 510-320 0–9 XXXall 10 · 5 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 FRNK MAIN CA
2013-06-03 510-680 0–9 XXXall 10 · 7 holders which blocks → CENTURYLINK COMMUNICATIONS, LLC 508J RICHMOND CA
2013-05-16 510-362 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 HAYWARD CA
2013-05-14 510-671 0–9 XXXall 10 · 7 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E OKLD ALMD CA
2013-03-07 510-646 0–9 XXXall 10 · 5 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E OKLD BKLY CA
2013-01-31 510-328 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 OKLD FRTVL CA
2013-01-18 510-598 0–9 XXXall 10 · 7 holders which blocks → T-MOBILE USA, INC. 6529 FRNK MAIN CA
2013-01-04 510-210 0–9 XXXall 10 · 6 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E RICHMOND CA
2012-12-07 510-298 0–9 XXXall 10 · 6 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 FRNK MAIN CA
2012-11-30 510-454 0–9 XXXall 10 · 4 holders which blocks → PACIFIC BELL 9740 OKLD TRNID CA
2012-09-14 510-775 0–9 XXXall 10 · 6 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E OKLD ALMD CA
2012-08-17 510-359 0–9 XXXall 10 · 4 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 HAYWARD CA
2012-08-17 510-398 0–9 XXXall 10 · 8 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E HAYWARD CA
2012-05-04 510-340 0–9 XXXall 10 · 3 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 HAYWARD CA
2012-04-13 510-370 0–9 XXXwhole prefix which blocks → PEERLESS NETWORK OF CALIFORNIA, LLC - CA 373F HAYWARD CA
2011-12-09 510-447 0–9 XXXall 10 · 6 holders which blocks → METROPCS, INC. 5562 RICHMOND CA
2011-11-04 510-294 0–9 XXXall 10 · 3 holders which blocks → METROPCS, INC. 5562 HAYWARD CA
2011-09-15 510-254 0–9 XXXall 10 · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 OKLD ALMD CA
2011-08-09 510-246 0–9 XXXall 10 · 5 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 HAYWARD CA
2011-07-25 510-244 0–9 XXXall 10 · 5 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E HAYWARD CA
2011-07-08 510-358 0–9 XXXall 10 · 5 holders which blocks → NEW CINGULAR WIRELESS PCS, LLC 6010 FRNK MAIN CA
2011-06-08 510-976 not yet reported which blocks → NORTH COUNTY COMMUNICATION CORPORATION - CA 7894 OKLD BKLY CA
2011-04-28 510-255 0–9 XXXall 10 · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E RICHMOND CA
2010-09-03 510-516 0–9 XXXall 10 · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E FRNK MAIN CA
2010-08-10 510-606 0–9 XXXall 10 · 5 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 HAYWARD CA
2010-07-06 510-509 0–9 XXXall 10 · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 FRNK MAIN CA
2010-02-22 510-470 0–9 XXXall 10 · 3 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E HAYWARD CA
2010-02-22 510-730 0–9 XXXall 10 · 4 holders which blocks → BANDWIDTH.COM CLEC, LLC - CA 981E RICHMOND CA
2010-02-09 510-460 0–9 XXXall 10 · 6 holders which blocks → CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA 6006 HAYWARD CA
2009-11-25 510-408 0–9 XXXall 10 · 3 holders which blocks → PACIFIC BELL 9740 ELSBR-PINL CA
2009-02-14 510-201 0–9 XXXall 10 · 2 holders which blocks → PEERLESS NETWORK OF CALIFORNIA, LLC - CA 373F OKLD MN-PD CA
2009-02-14 510-443 0–9 XXXall 10 · 2 holders which blocks → PEERLESS NETWORK OF CALIFORNIA, LLC - CA 373F FRNK MAIN CA
2008-11-12 510-200 0–9 XXXall 10 · 6 holders which blocks → METROPCS, INC. 5562 HAYWARD CA
2008-11-07 510-423 0–9 XXXall 10 · 8 holders which blocks → PAETEC ITEL, LLC 829J OKLD BKLY CA
2008-08-28 510-397 0–9 XXXall 10 · 3 holders which blocks → COMCAST PHONE OF CALIFORNIA, LLC 394L HAYWARD CA
2008-08-07 510-371 0–9 XXXall 10 · 7 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - CA 8826 FRNK MAIN 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.