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 501
T-MOBILE USA, INC. 42
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
2025-12-05 501-591 0XXX1XXX2XXX3XXX4XXX7XXX9XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 BEEBE AR
2021-10-11 501-489 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 MALVERN AR
2021-01-13 501-449 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CABOT AR
2020-03-31 501-403 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 BENTON AR
2020-03-31 501-409 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 BENTON AR
2018-08-23 501-290 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 SEARCY AR
2018-03-21 501-273 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 CONWAY AR
2017-08-11 501-236 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 SEARCY AR
2017-03-06 501-293 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 HOTSPRINGS AR
2016-08-18 501-435 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
2016-08-18 501-443 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 BENTON AR
2014-12-10 501-510 0–9 XXXall 10 · 7 holders which blocks → T-MOBILE USA, INC. 6529 LONOKE AR
2014-08-20 501-502 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
2014-03-28 501-415 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 LONOKE AR
2014-03-19 501-507 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 BENTON AR
2014-01-30 501-703 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 LONOKE AR
2012-11-01 501-420 1XXX2XXX3XXX4XXX5XXX6XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
2011-10-14 501-264 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
2011-10-10 501-267 0–9 XXXall 10 · 7 holders which blocks → T-MOBILE USA, INC. 6529 MALVERN AR
2011-10-06 501-308 1XXX2XXX3XXX4XXX8XXX9XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
2011-09-22 501-248 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
2011-08-25 501-216 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
2011-08-02 501-444 0XXX1XXX2XXX4XXX5XXX8XXX9XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
2011-06-22 501-272 0XXX1XXX5XXX7XXX8XXX9XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
2011-06-02 501-243 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
2011-05-06 501-237 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 LONOKE AR
2005-10-17 501-613 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
2004-01-27 501-442 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
2002-12-31 501-277 1XXX2XXX3XXX5XXX6XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 GREENBRIER AR
2001-08-20 501-473 2XXX3XXX4XXX5XXX which blocks → T-MOBILE USA, INC. 6529 SEARCY AR
2001-01-23 501-818 8XXX which blocks → T-MOBILE USA, INC. 6529 MALVERN AR
— 501-240 none assigned yet which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
— 501-256 0XXX8XXX which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
— 501-260 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
— 501-310 none assigned yet which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
— 501-346 0XXX1XXX2XXX which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
— 501-348 1XXX which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
— 501-349 none assigned yet which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
— 501-606 5XXX7XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 CABOT AR
— 501-693 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 HOTSPRINGS AR
— 501-779 8XXX which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR
— 501-960 none assigned yet which blocks → T-MOBILE USA, INC. 6529 LITTLEROCK AR

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.