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 |
|---|---|---|---|---|---|---|
| — | 231-204 | not yet reported which blocks → | SPOK, INC. | 6630 | FIFE LAKE | MI |
| — | 231-255 | not yet reported which blocks → | SPOK, INC. | 6630 | ONEKAMA | MI |
| — | 231-315 | not yet reported which blocks → | SPOK, INC. | 6630 | MUSKEGON | MI |
| — | 231-317 | not yet reported which blocks → | SPOK, INC. | 6630 | BOYNE CITY | MI |
| — | 231-318 | not yet reported which blocks → | SPOK, INC. | 6630 | TRAVERSECY | MI |
| — | 231-336 | not yet reported which blocks → | SPOK, INC. | 6630 | LUDINGTON | MI |
| — | 231-593 | not yet reported which blocks → | SPOK, INC. | 6630 | CADILLAC | MI |
| — | 231-596 | not yet reported which blocks → | SPOK, INC. | 6630 | HARBOR SPG | MI |
| — | 231-604 | not yet reported which blocks → | SPOK, INC. | 6630 | KALKASKA | MI |
| — | 231-605 | not yet reported which blocks → | SPOK, INC. | 6630 | NEWAYGO | MI |
| — | 231-608 | not yet reported which blocks → | SPOK, INC. | 6630 | FRANKFORT | 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.