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 720
T-MOBILE USA, INC. 132
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
2009-03-20 720-421 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 DENVER CO
2009-01-13 720-401 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 DENVER CO
2008-07-22 720-999 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 DENVER CO
2002-02-04 720-427 not yet reported which blocks → T-MOBILE USA, INC. 6529 DENVER CO
2001-05-14 720-333 none assigned yet which blocks → T-MOBILE USA, INC. 6529 DENVER CO
2001-05-14 720-334 7XXX8XXX which blocks → T-MOBILE USA, INC. 6529 DENVER CO
2001-05-14 720-335 5XXX6XXX7XXX8XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 DENVER CO
2001-04-19 720-319 7XXX8XXX which blocks → T-MOBILE USA, INC. 6529 DENVER CO
2001-02-20 720-312 none assigned yet which blocks → T-MOBILE USA, INC. 6529 DENVER CO
2001-02-20 720-313 none assigned yet which blocks → T-MOBILE USA, INC. 6529 DENVER CO
2001-02-20 720-314 8XXX which blocks → T-MOBILE USA, INC. 6529 DENVER CO
2001-01-29 720-203 none assigned yet which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-205 none assigned yet which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-209 0XXX1XXX2XXX4XXX8XXX which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-217 not yet reported which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-218 4XXX which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-220 not yet reported which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-231 not yet reported which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-232 1XXX2XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-233 1XXX2XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-234 1XXX2XXX which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-235 0XXX1XXX2XXX3XXX4XXX5XXX7XXX8XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-236 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-238 2XXX3XXX5XXX7XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-252 0XXX1XXX2XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-253 0XXX1XXX2XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-254 0XXX1XXX2XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-255 0XXX1XXX2XXX · 3 holders which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-256 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-260 4XXX which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-261 not yet reported which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-270 0XXX which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-271 3XXX4XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-280 not yet reported which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-290 none assigned yet which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-291 none assigned yet which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-299 not yet reported which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-300 2XXX3XXX8XXX which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-301 none assigned yet which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-317 0XXX2XXX6XXX8XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-318 0XXX2XXX3XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-323 not yet reported which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-331 none assigned yet which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-339 2XXX which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-341 not yet reported which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-350 4XXX which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-351 4XXX which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-352 not yet reported which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-353 4XXX which blocks → T-MOBILE USA, INC. 6529 DENVER CO
— 720-371 none assigned yet which blocks → T-MOBILE USA, INC. 6529 DENVER CO

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.