NumberResearch Membership · Data 09/21/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/21/2026

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 928
T-MOBILE USA, INC. 40
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
2025-11-06 928-553 8XXX9XXX which blocks → T-MOBILE USA, INC. 6529 BULLHEADCY AZ
2024-02-07 928-518 0XXX2XXX6XXX7XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 SEDONA AZ
2022-08-12 928-435 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 BULLHEADCY AZ
2022-01-07 928-464 0–9 XXXall 10 · 7 holders which blocks → T-MOBILE USA, INC. 6529 WICKENBURG AZ
2022-01-07 928-469 0XXX1XXX9XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 PARKER AZ
2021-10-01 928-450 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 BULLHEADCY AZ
2021-08-24 928-418 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 KINGMAN AZ
2021-07-27 928-417 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 SAFFORD AZ
2016-07-15 928-256 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 YUMA AZ
2016-06-09 928-250 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 SAFFORD AZ
2010-07-23 928-514 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 BULLHEADCY AZ
2010-03-15 928-259 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 YUMA AZ
2007-09-07 928-315 0–9 XXXall 10 · 7 holders which blocks → T-MOBILE USA, INC. 6529 SOMERTON AZ
2006-01-31 928-488 none assigned yet which blocks → T-MOBILE USA, INC. 6529 YUMA AZ
2005-06-02 928-550 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 SOMERTON AZ
2004-09-22 928-310 3XXX4XXX5XXX6XXX7XXX8XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 FLAGSTAFF AZ
2004-09-22 928-420 7XXX8XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 PRESCOTT AZ
2004-09-22 928-451 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 SEDONA AZ
2002-09-17 928-230 0XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 LKHAVASUCY AZ
2002-08-28 928-862 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → T-MOBILE USA, INC. 6529 SEDONA AZ
2002-08-28 928-863 2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → T-MOBILE USA, INC. 6529 FLAGSTAFF AZ
2002-08-07 928-237 1XXX2XXX3XXX4XXX5XXX8XXX9XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 PRESCOTT AZ
2002-08-07 928-239 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 SEDONA AZ
2002-07-03 928-232 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 WICKENBURG AZ
2002-04-17 928-533 none assigned yet which blocks → T-MOBILE USA, INC. 6529 PRESCOTT AZ
2002-01-31 928-225 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 FLAGSTAFF AZ
2002-01-29 928-399 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 SEDONA AZ
2002-01-29 928-458 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 PRESCOTT AZ
2002-01-15 928-446 0XXX3XXX4XXX5XXX7XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 YUMA AZ
2002-01-15 928-848 2XXX6XXX7XXX8XXX9XXX which blocks → T-MOBILE USA, INC. 6529 PRESCOTT AZ
2001-08-15 928-542 0XXX2XXX3XXX4XXX5XXX7XXX8XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 BULLHEADCY AZ
2001-04-16 928-486 none assigned yet which blocks → T-MOBILE USA, INC. 6529 LKHAVASUCY AZ
2001-03-12 928-279 0XXX8XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 KINGMAN AZ
— 928-246 none assigned yet which blocks → T-MOBILE USA, INC. 6529 YUMA AZ
— 928-261 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 YUMA AZ
— 928-388 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 YUMA AZ
— 928-459 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 YUMA AZ
— 928-600 8XXX which blocks → T-MOBILE USA, INC. 6529 FLAGSTAFF AZ
— 928-710 none assigned yet which blocks → T-MOBILE USA, INC. 6529 PRESCOTT AZ
— 928-941 4XXX5XXX which blocks → T-MOBILE USA, INC. 6529 YUMA AZ

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/21/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.