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 617
TC SYSTEMS, INC. 41
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
2008-04-24 617-672 0–9 XXXwhole prefix which blocks → TC SYSTEMS, INC. 7135 BOSTON MA
2001-12-15 617-386 0XXX3XXX6XXX9XXX · 2 holders which blocks → TC SYSTEMS, INC. 7135 CAMBRIDGE MA
— 617-217 1XXX4XXX8XXX9XXX · 3 holders which blocks → TC SYSTEMS, INC. 7135 BOSTON MA
— 617-218 7XXX which blocks → TC SYSTEMS, INC. 7135 CAMBRIDGE MA
— 617-239 1XXX5XXX9XXX · 3 holders which blocks → TC SYSTEMS, INC. 7135 BOSTON MA
— 617-250 0XXX7XXX8XXX · 2 holders which blocks → TC SYSTEMS, INC. 7135 CAMBRIDGE MA
— 617-300 0XXX7XXX8XXX9XXX · 4 holders which blocks → TC SYSTEMS, INC. 7135 CAMBRIDGE MA
— 617-316 not yet reported which blocks → TC SYSTEMS, INC. 7135 BOSTON MA
— 617-378 1XXX2XXX5XXX7XXX8XXX which blocks → TC SYSTEMS, INC. 7135 BOSTON MA
— 617-385 not yet reported which blocks → TC SYSTEMS, INC. 7135 BOSTON MA
— 617-392 not yet reported which blocks → TC SYSTEMS, INC. 7135 BOSTON MA
— 617-396 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → TC SYSTEMS, INC. 7135 BROOKLINE MA
— 617-397 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → TC SYSTEMS, INC. 7135 CAMBRIDGE MA
— 617-406 7XXX8XXX9XXX · 2 holders which blocks → TC SYSTEMS, INC. 7135 BOSTON MA
— 617-431 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → TC SYSTEMS, INC. 7135 NEWTON MA
— 617-433 0XXX1XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → TC SYSTEMS, INC. 7135 MILTON MA
— 617-454 4XXX5XXX7XXX8XXX · 4 holders which blocks → TC SYSTEMS, INC. 7135 NEWTON MA
— 617-476 not yet reported which blocks → TC SYSTEMS, INC. 7135 BOSTON MA
— 617-487 1XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 5 holders which blocks → TC SYSTEMS, INC. 7135 BROOKLINE MA
— 617-488 9XXX which blocks → TC SYSTEMS, INC. 7135 BOSTON MA
— 617-528 0XXX8XXX9XXX · 2 holders which blocks → TC SYSTEMS, INC. 7135 CAMBRIDGE MA
— 617-530 0XXX1XXX · 2 holders which blocks → TC SYSTEMS, INC. 7135 BOSTON MA
— 617-563 not yet reported which blocks → TC SYSTEMS, INC. 7135 BOSTON MA
— 617-598 not yet reported which blocks → TC SYSTEMS, INC. 7135 BOSTON MA
— 617-612 0XXX3XXX4XXX5XXX6XXX8XXX · 5 holders which blocks → TC SYSTEMS, INC. 7135 WATERTOWN MA
— 617-613 not yet reported which blocks → TC SYSTEMS, INC. 7135 CAMBRIDGE MA
— 617-616 0XXX2XXX3XXX5XXX8XXX9XXX · 5 holders which blocks → TC SYSTEMS, INC. 7135 SOMERVILLE MA
— 617-646 9XXX which blocks → TC SYSTEMS, INC. 7135 BOSTON MA
— 617-663 0XXX6XXX8XXX · 2 holders which blocks → TC SYSTEMS, INC. 7135 NEWTON MA
— 617-691 0XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → TC SYSTEMS, INC. 7135 QUINCY MA
— 617-692 0XXX2XXX · 2 holders which blocks → TC SYSTEMS, INC. 7135 BOSTON MA
— 617-717 2XXX4XXX6XXX8XXX9XXX · 3 holders which blocks → TC SYSTEMS, INC. 7135 BOSTON MA
— 617-747 not yet reported which blocks → TC SYSTEMS, INC. 7135 BOSTON MA
— 617-766 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → TC SYSTEMS, INC. 7135 SO BOSTON MA
— 617-793 2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → TC SYSTEMS, INC. 7135 QUINCY MA
— 617-824 0XXX which blocks → TC SYSTEMS, INC. 7135 BOSTON MA
— 617-850 2XXX5XXX9XXX · 3 holders which blocks → TC SYSTEMS, INC. 7135 BOSTON MA
— 617-880 9XXX which blocks → TC SYSTEMS, INC. 7135 BOSTON MA
— 617-912 not yet reported which blocks → TC SYSTEMS, INC. 7135 BOSTON MA
— 617-932 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → TC SYSTEMS, INC. 7135 BELMONT MA
— 617-942 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → TC SYSTEMS, INC. 7135 JAMAICA PL MA

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.