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 323
T-MOBILE USA, INC. 64
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
Clear Download CSV ↓
Recent NPA-NXX prefix assignments
AssignedNPA-NXXThousands-blocks taken (last-4 opening)Code holderOCNRate centerState
2024-04-12 323-824 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 14 CA
2019-03-19 323-949 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 MONTEBELLO CA
2017-04-07 323-880 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 09 CA
2016-11-11 323-994 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 14 CA
2016-10-18 323-831 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 05 CA
2016-09-26 323-925 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 03 CA
2016-07-22 323-530 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 MONTEBELLO CA
2016-07-15 323-961 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 LSAN DA 09 CA
2016-03-09 323-616 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 03 CA
2015-11-17 323-716 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 11 CA
2015-09-22 323-612 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 04 CA
2015-08-26 323-615 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 09 CA
2015-08-26 323-840 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 11 CA
2015-05-05 323-690 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 11 CA
2015-04-13 323-975 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 LSAN DA 03 CA
2015-03-09 323-847 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 13 CA
2015-02-24 323-794 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 14 CA
2015-02-09 323-926 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 MONTEBELLO CA
2015-02-06 323-740 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 11 CA
2015-02-03 323-561 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 03 CA
2014-10-17 323-597 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 MONTEBELLO CA
2014-09-08 323-688 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 14 CA
2014-01-27 323-621 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 MONTEBELLO CA
2013-07-15 323-714 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 MONTEBELLO CA
2007-10-10 323-703 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 14 CA
2007-08-29 323-542 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 LSAN DA 03 CA
2007-07-03 323-519 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 MONTEBELLO CA
2007-07-03 323-532 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 LSAN DA 03 CA
2007-05-18 323-470 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 LSAN DA 03 CA
2007-04-24 323-455 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 09 CA
2006-10-16 323-747 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 03 CA
2006-10-04 323-892 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 03 CA
2006-09-21 323-570 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 09 CA
2006-04-25 323-742 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 MONTEBELLO CA
2006-02-22 323-861 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 09 CA
2002-09-19 323-350 not yet reported which blocks → T-MOBILE USA, INC. 6529 LSAN DA 04 CA
2002-09-19 323-788 not yet reported which blocks → T-MOBILE USA, INC. 6529 LSAN DA 05 CA
2002-06-14 323-712 6XXX7XXX which blocks → T-MOBILE USA, INC. 6529 MONTEBELLO CA
2002-05-17 323-620 not yet reported which blocks → T-MOBILE USA, INC. 6529 LSAN DA 11 CA
2002-05-17 323-702 not yet reported which blocks → T-MOBILE USA, INC. 6529 LSAN DA 12 CA
2002-05-17 323-842 not yet reported which blocks → T-MOBILE USA, INC. 6529 LSAN DA 03 CA
2002-05-17 323-899 not yet reported which blocks → T-MOBILE USA, INC. 6529 LSAN DA 13 CA
2001-12-26 323-304 not yet reported which blocks → T-MOBILE USA, INC. 6529 LSAN DA 14 CA
2001-09-19 323-841 not yet reported which blocks → T-MOBILE USA, INC. 6529 LSAN DA 09 CA
— 323-251 none assigned yet which blocks → T-MOBILE USA, INC. 6529 LSAN DA 14 CA
— 323-286 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 03 CA
— 323-377 none assigned yet which blocks → T-MOBILE USA, INC. 6529 LSAN DA 14 CA
— 323-379 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 04 CA
— 323-381 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 13 CA
— 323-403 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 LSAN DA 12 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.