NumberResearch Membership · Data 09/22/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/22/2026

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
— 513-289 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-290 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-293 not yet reported which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-295 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-307 not yet reported which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-328 not yet reported which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-348 1XXX2XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-349 0XXX2XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-383 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-435 6XXX7XXX8XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 MIDDLETOWN OH
— 513-461 0XXX2XXX6XXX7XXX8XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 OXFORD OH
— 513-464 4XXX5XXX9XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 MIDDLETOWN OH
— 513-544 0XXX1XXX2XXX which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-545 0XXX1XXX2XXX which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-546 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-571 0XXX which blocks → T-MOBILE USA, INC. 6529 MIDDLETOWN OH
— 513-602 not yet reported which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-615 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-616 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-617 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-623 none assigned yet which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-652 4XXX8XXX which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-804 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 MIDDLETOWN OH
— 513-807 not yet reported which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-836 1XXX2XXX3XXX4XXX5XXX8XXX9XXX · 4 holders which blocks → T-MOBILE USA, INC. 6529 LEBANON OH
— 513-850 0XXX2XXX6XXX7XXX8XXX · 2 holders which blocks → T-MOBILE USA, INC. 6529 LEBANON OH
— 513-884 not yet reported which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-885 not yet reported which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH
— 513-886 not yet reported which blocks → T-MOBILE USA, INC. 6529 CINCINNATI OH

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/22/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.