NumberResearchRecent prefix assignments
0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/27/2026
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 |
|---|---|---|---|---|---|---|
| 2025-12-26 | 353-353 | 3XXX4XXX5XXX6XXX7XXX8XXX which blocks → | ONVOY, LLC - WI | 225C | BELLEVILLE | WI |
| 2025-12-26 | 353-529 | 7XXX8XXX9XXX which blocks → | ONVOY, LLC - WI | 225C | DE FOREST | WI |
| 2025-10-03 | 353-200 | 0–9 XXXall 10 · 4 holders which blocks → | ONVOY, LLC - WI | 225C | MADISON | WI |
| 2025-08-29 | 353-222 | 0XXX2XXX3XXX4XXX8XXX · 3 holders which blocks → | ONVOY, LLC - WI | 225C | LONE ROCK | WI |
| 2025-08-29 | 353-333 | 0XXX3XXX4XXX5XXX · 2 holders which blocks → | ONVOY, LLC - WI | 225C | MONTELLO | WI |
| 2025-08-29 | 353-444 | 4XXX5XXX6XXX which blocks → | ONVOY, LLC - WI | 225C | BLOOM CITY | WI |
| 2025-08-29 | 353-666 | 6XXX7XXX8XXX which blocks → | ONVOY, LLC - WI | 225C | CENTERVL | WI |
| 2025-08-29 | 353-777 | 7XXX8XXX9XXX which blocks → | ONVOY, LLC - WI | 225C | MAZOMANIE | WI |
| 2025-08-29 | 353-888 | 0XXX8XXX9XXX which blocks → | ONVOY, LLC - WI | 225C | ALBANY | WI |
| 2025-08-21 | 353-999 | 0XXX9XXX which blocks → | ONVOY, LLC - WI | 225C | ITHACA | WI |
Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/27/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.