NumberResearch Membership · Data 09/19/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/19/2026

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 520
T-MOBILE USA, INC. 84
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
2026-01-09 520-765 0XXX1XXX2XXX3XXX7XXX9XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 CASAGRANDE AZ
2025-10-28 520-764 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CASAGRANDE AZ
2025-07-11 520-763 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CASAGRANDE AZ
2025-03-25 520-757 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CASAGRANDE AZ
2024-02-16 520-728 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CASAGRANDE AZ
2023-11-09 520-701 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CASAGRANDE AZ
2023-05-31 520-435 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 WILLCOX AZ
2022-09-20 520-660 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CASAGRANDE AZ
2022-03-10 520-634 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CASAGRANDE AZ
2021-10-26 520-596 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2021-08-24 520-556 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 SIERRAVIST AZ
2021-07-19 520-553 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CASAGRANDE AZ
2021-05-14 520-543 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2021-04-02 520-504 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 SIERRAVIST AZ
2021-01-11 520-534 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2020-12-23 520-637 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CASAGRANDE AZ
2020-12-08 520-535 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2020-11-23 520-473 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 SIERRAVIST AZ
2020-05-11 520-479 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2019-08-23 520-380 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 CASAGRANDE AZ
2016-09-14 520-274 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2016-09-14 520-402 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 BENSON AZ
2016-03-14 520-244 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2015-04-07 520-635 0–9 XXXall 10 · 7 holders which blocks → T-MOBILE USA, INC. 6529 CASAGRANDE AZ
2015-01-02 520-965 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2014-10-24 520-658 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2014-09-23 520-283 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2014-09-22 520-788 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CASAGRANDE AZ
2014-08-19 520-257 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2013-06-25 520-213 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 CASAGRANDE AZ
2013-04-19 520-499 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2013-01-11 520-286 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2013-01-11 520-427 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2012-11-16 520-474 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2012-10-31 520-373 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2012-09-17 520-460 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2012-05-17 520-332 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2012-04-24 520-365 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2012-02-24 520-789 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2007-06-06 520-443 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
2002-11-06 520-234 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 SIERRAVIST AZ
2002-08-09 520-265 1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → T-MOBILE USA, INC. 6529 BENSON AZ
2002-08-09 520-266 6XXX9XXX which blocks → T-MOBILE USA, INC. 6529 SIERRAVIST AZ
2002-05-31 520-220 2XXX3XXX4XXX5XXX7XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 SIERRAVIST AZ
2002-05-16 520-227 none assigned yet which blocks → T-MOBILE USA, INC. 6529 SIERRAVIST AZ
2001-05-15 520-313 2XXX5XXX6XXX7XXX8XXX which blocks → T-MOBILE USA, INC. 6529 NOGALES AZ
2001-05-15 520-619 2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 NOGALES AZ
2001-01-29 520-256 none assigned yet which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ
— 520-238 none assigned yet which blocks → T-MOBILE USA, INC. 6529 YUMA AZ
— 520-245 not yet reported which blocks → T-MOBILE USA, INC. 6529 TUCSON AZ

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/19/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.