NumberResearchRecent prefix assignments
0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/20/2026
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.
| Assigned | NPA-NXX | Thousands-blocks taken (last-4 opening) | Code holder | OCN | Rate center | State |
|---|---|---|---|---|---|---|
| 2005-12-07 | 517-701 | 0–9 XXXall 10 · 6 holders which blocks → | 123.NET, LLC | 2550 | CLINTON | MI |
| 2003-02-21 | 517-992 | 0–9 XXXall 10 · 8 holders which blocks → | 123.NET, LLC | 2550 | WILLIAMSTN | MI |
| 2002-08-12 | 517-544 | not yet reported which blocks → | 123.NET, LLC | 2550 | JACKSON | MI |
| 2002-08-12 | 517-584 | not yet reported which blocks → | 123.NET, LLC | 2550 | ALBION | MI |
| 2002-08-12 | 517-609 | not yet reported which blocks → | 123.NET, LLC | 2550 | JONESVILLE | MI |
| 2002-08-12 | 517-642 | not yet reported which blocks → | 123.NET, LLC | 2550 | MUNITH | MI |
| 2002-08-12 | 517-679 | not yet reported which blocks → | 123.NET, LLC | 2550 | LANSING | MI |
| 2002-08-12 | 517-732 | 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → | 123.NET, LLC | 2550 | PORTLAND | MI |
| 2002-08-12 | 517-762 | not yet reported which blocks → | 123.NET, LLC | 2550 | DANSVILLE | MI |
| 2002-08-12 | 517-785 | not yet reported which blocks → | 123.NET, LLC | 2550 | ONONDAGA | MI |
| 2002-08-12 | 517-828 | not yet reported which blocks → | 123.NET, LLC | 2550 | HILLSDALE | MI |
| 2002-08-12 | 517-873 | not yet reported which blocks → | 123.NET, LLC | 2550 | CHARLOTTE | MI |
| 2001-12-27 | 517-736 | 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → | 123.NET, LLC | 2550 | COLDWATER | MI |
| 2001-11-01 | 517-682 | 0XXX1XXX2XXX4XXX5XXX6XXX8XXX9XXX · 6 holders which blocks → | 123.NET, LLC | 2550 | BLISSFIELD | MI |
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.