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 |
|---|---|---|---|---|---|---|
| 2025-12-03 | 307-435 | 7XXX9XXX · 2 holders which blocks → | T-MOBILE USA, INC. | 6529 | SHERIDAN | WY |
| 2025-11-06 | 307-385 | 0XXX7XXX9XXX · 2 holders which blocks → | T-MOBILE USA, INC. | 6529 | JACKSON | WY |
| 2025-05-06 | 307-485 | 0XXX1XXX2XXX3XXX4XXX7XXX8XXX9XXX · 3 holders which blocks → | T-MOBILE USA, INC. | 6529 | CASPER | WY |
| 2025-04-08 | 307-482 | 0XXX8XXX9XXX · 2 holders which blocks → | T-MOBILE USA, INC. | 6529 | WHEATLAND | WY |
| 2025-02-05 | 307-478 | 3XXX5XXX6XXX7XXX8XXX9XXX which blocks → | T-MOBILE USA, INC. | 6529 | LA GRANGE | WY |
| 2023-12-01 | 307-428 | 0XXX1XXX2XXX3XXX4XXX7XXX8XXX9XXX · 2 holders which blocks → | T-MOBILE USA, INC. | 6529 | DOUGLAS | WY |
| 2022-03-24 | 307-419 | 0–9 XXXall 10 · 5 holders which blocks → | T-MOBILE USA, INC. | 6529 | CODY | WY |
| 2022-03-22 | 307-410 | 0–9 XXXall 10 · 3 holders which blocks → | T-MOBILE USA, INC. | 6529 | POWELL | WY |
| 2021-05-21 | 307-394 | 0–9 XXXall 10 · 6 holders which blocks → | T-MOBILE USA, INC. | 6529 | CASPER | WY |
| 2020-07-29 | 307-355 | 0–9 XXXall 10 · 3 holders which blocks → | T-MOBILE USA, INC. | 6529 | LA GRANGE | WY |
| 2001-03-14 | 307-203 | 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → | T-MOBILE USA, INC. | 6529 | JACKSON | WY |
| — | 307-220 | 4XXX5XXX6XXX9XXX which blocks → | T-MOBILE USA, INC. | 6529 | CHEYENNE | WY |
| — | 307-221 | 8XXX which blocks → | T-MOBILE USA, INC. | 6529 | CHEYENNE | WY |
| — | 307-920 | 2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX which blocks → | T-MOBILE USA, INC. | 6529 | CHEYENNE | WY |
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.