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 661
T-MOBILE USA, INC. 56
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
2025-03-21 661-672 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 ARVIN CA
2024-09-17 661-736 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 ARVIN CA
2024-09-12 661-652 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 SNCA NHCS CA
2024-01-23 661-996 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 BKFD MAIN CA
2022-09-02 661-594 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 SHAFTER CA
2022-04-25 661-653 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 DELANO CA
2021-12-10 661-569 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 BKFD MAIN CA
2021-12-08 661-625 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 SNCA NHCS CA
2021-11-15 661-936 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 PLDL PLDL CA
2021-10-28 661-531 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 ARVIN CA
2021-06-30 661-519 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 ARVIN CA
2021-02-16 661-627 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 SNCA NHCS CA
2020-10-16 661-545 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 DELANO CA
2020-07-28 661-503 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 PLDL PLDL CA
2019-04-12 661-690 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 DELANO CA
2019-03-19 661-566 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 PLDL PLDL CA
2017-01-16 661-403 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 PLDL PLDL CA
2016-11-14 661-314 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 BKFD MAIN CA
2016-08-29 661-416 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 ARVIN CA
2016-07-15 661-593 0–9 XXXall 10 · 8 holders which blocks → T-MOBILE USA, INC. 6529 SNCA NHCS CA
2016-05-24 661-365 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 PLDL PLDL CA
2015-08-03 661-576 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 PLDL PLDL CA
2015-03-09 661-421 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 BKFD MAIN CA
2014-12-22 661-488 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 LANCASTER CA
2014-10-14 661-445 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 LANCASTER CA
2013-12-09 661-447 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 BKFD MAIN CA
2012-09-24 661-429 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 LANCASTER CA
2012-02-24 661-418 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 LANCASTER CA
2006-02-22 661-794 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 PLDL PLDL CA
2002-03-12 661-735 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 BKFD SOUTH CA
2002-01-16 661-220 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 ARVIN CA
2002-01-16 661-221 1XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 MOJAVE CA
2002-01-16 661-292 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 SHAFTER CA
2002-01-16 661-293 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 TAFT CA
2002-01-16 661-300 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 TEHACHAPI CA
2001-12-14 661-317 not yet reported which blocks → T-MOBILE USA, INC. 6529 PLDL PLDL CA
2001-12-14 661-373 not yet reported which blocks → T-MOBILE USA, INC. 6529 SNCA NHCS CA
2001-12-14 661-472 not yet reported which blocks → T-MOBILE USA, INC. 6529 BKFD MAIN CA
2001-11-13 661-750 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 TEHACHAPI CA
2001-10-10 661-492 none assigned yet which blocks → T-MOBILE USA, INC. 6529 LANCASTER CA
2001-10-10 661-709 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 DELANO CA
— 661-201 none assigned yet which blocks → T-MOBILE USA, INC. 6529 BKFD MAIN CA
— 661-232 0XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → T-MOBILE USA, INC. 6529 MOJAVE CA
— 661-234 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 PLDL PLDL CA
— 661-247 0XXX3XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 ARVIN CA
— 661-444 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 BKFD MAIN CA
— 661-547 none assigned yet which blocks → T-MOBILE USA, INC. 6529 LANCASTER CA
— 661-606 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 ARVIN CA
— 661-674 0XXX3XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 LANCASTER CA
— 661-675 3XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 PLDL PLDL 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.