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 858
T-MOBILE USA, INC. 44
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
2025-11-28 858-445 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 SNDG MRMS CA
2025-10-21 858-443 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 CHULAVISTA CA
2024-09-19 858-415 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 SNDG SNDG CA
2024-08-30 858-407 0XXX1XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 CHULAVISTA CA
2024-05-31 858-902 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CHULAVISTA CA
2023-10-10 858-389 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CHULAVISTA CA
2022-10-28 858-341 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 CHULAVISTA CA
2021-11-18 858-330 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 RNCHOPNQTS CA
2021-03-24 858-319 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 LA JOLLA CA
2021-03-11 858-313 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 DEL MAR CA
2021-03-10 858-308 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 SNDG LVTA CA
2021-02-17 858-305 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 SNDG MRMS CA
2021-01-08 858-241 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 LA JOLLA CA
2019-02-28 858-290 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 DEL MAR CA
2017-11-22 858-214 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 LA JOLLA CA
2017-05-22 858-209 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 DEL MAR CA
2015-09-25 858-267 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 SNDG MRMS CA
2015-03-11 858-262 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 SNDG LVTA CA
2015-02-18 858-261 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 DEL MAR CA
2014-10-08 858-252 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 DEL MAR CA
2013-07-22 858-260 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 LA JOLLA CA
2006-09-21 858-652 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 LA JOLLA CA
2002-08-30 858-504 2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 RNCHOSANFE CA
2002-08-30 858-610 7XXX which blocks → T-MOBILE USA, INC. 6529 SNDG MRMS CA
2002-08-30 858-717 6XXX7XXX8XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 SNDG LVTA CA
2002-08-30 858-733 3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 RNCHOPNQTS CA
2002-08-30 858-776 3XXX4XXX5XXX6XXX7XXX8XXX which blocks → T-MOBILE USA, INC. 6529 RNCHOBRNDO CA
2002-04-01 858-602 0XXX1XXX2XXX3XXX4XXX5XXX8XXX9XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 POWAY CA
2002-01-18 858-220 5XXX7XXX8XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 LA JOLLA CA
2002-01-16 858-205 1XXX6XXX which blocks → T-MOBILE USA, INC. 6529 DEL MAR CA
2001-12-14 858-231 not yet reported which blocks → T-MOBILE USA, INC. 6529 POWAY CA
2001-12-14 858-405 not yet reported which blocks → T-MOBILE USA, INC. 6529 LA JOLLA CA
2001-09-24 858-583 5XXX7XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 SNDG LVTA CA
— 858-212 0XXX which blocks → T-MOBILE USA, INC. 6529 POWAY CA
— 858-213 0XXX2XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 POWAY CA
— 858-254 none assigned yet which blocks → T-MOBILE USA, INC. 6529 POWAY CA
— 858-518 none assigned yet which blocks → T-MOBILE USA, INC. 6529 LA JOLLA CA
— 858-663 none assigned yet which blocks → T-MOBILE USA, INC. 6529 POWAY CA
— 858-682 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 POWAY CA
— 858-752 0XXX1XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 LA JOLLA CA
— 858-829 0XXX which blocks → T-MOBILE USA, INC. 6529 POWAY CA
— 858-864 1XXX9XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 LA JOLLA CA
— 858-883 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → T-MOBILE USA, INC. 6529 POWAY CA
— 858-967 none assigned yet which blocks → T-MOBILE USA, INC. 6529 LA JOLLA CA

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.