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 513
T-MOBILE USA, INC. 79
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
2022-12-08 513-610 0XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 SEVEN MILE OH
2022-06-08 513-957 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 SEVEN MILE OH
2021-09-08 513-879 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2021-04-13 513-838 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2021-04-01 513-764 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2021-01-27 513-809 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 5 holders which blocks → T-MOBILE USA, INC. 6529 LEBANON OH
2021-01-27 513-822 0–9 XXXall 10 · 5 holders which blocks → T-MOBILE USA, INC. 6529 MIDDLETOWN OH
2020-07-17 513-690 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 SEVEN MILE OH
2015-07-31 513-918 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2015-06-25 513-996 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2012-03-12 513-704 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2012-03-05 513-620 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2012-03-02 513-609 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2011-12-21 513-510 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2011-12-21 513-580 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2011-11-16 513-413 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2011-09-20 513-302 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2011-09-20 513-501 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2011-08-04 513-394 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2011-08-04 513-399 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2011-07-05 513-462 0–9 XXXwhole prefix which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2011-05-27 513-306 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2011-05-27 513-356 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2011-03-16 513-301 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2011-02-25 513-568 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2011-02-23 513-888 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2010-12-15 513-400 0–9 XXXall 10 · 4 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2009-10-09 513-208 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2009-10-09 513-223 0–9 XXXall 10 · 6 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2009-10-09 513-250 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2009-09-22 513-655 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2007-05-23 513-578 0–9 XXXall 10 · 2 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2004-06-23 513-291 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 SEVEN MILE OH
2002-04-09 513-331 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 LEBANON OH
2002-03-15 513-283 0–9 XXXall 10 · 3 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
2001-04-30 513-849 0XXX1XXX2XXX3XXX4XXX5XXX7XXX8XXX · 5 holders which blocks → T-MOBILE USA, INC. 6529 MIDDLETOWN OH
2001-03-06 513-678 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-200 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-225 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-226 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-227 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-237 not yet reported which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-238 not yet reported which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-252 0XXX2XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-253 0XXX which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-254 0XXX2XXX which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-257 0XXX2XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-258 0XXX2XXX which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-259 0XXX2XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-266 9XXX which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH

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.