NumberResearchRecent prefix assignments
0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/21/2026
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 |
|---|---|---|---|---|---|---|
| — | 937-603 | none assigned yet which blocks → | T-MOBILE USA, INC. | 6529 | DAYTON | OH |
| — | 937-604 | none assigned yet which blocks → | T-MOBILE USA, INC. | 6529 | DAYTON | OH |
| — | 937-605 | none assigned yet which blocks → | T-MOBILE USA, INC. | 6529 | SPRINGFLD | OH |
| — | 937-606 | 2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → | T-MOBILE USA, INC. | 6529 | PIQUA | OH |
| — | 937-608 | 2XXX3XXX4XXX9XXX · 2 holders which blocks → | T-MOBILE USA, INC. | 6529 | DAYTON | OH |
| — | 937-626 | 8XXX which blocks → | T-MOBILE USA, INC. | 6529 | DAYTON | OH |
| — | 937-673 | none assigned yet which blocks → | T-MOBILE USA, INC. | 6529 | DAYTON | OH |
| — | 937-674 | none assigned yet which blocks → | T-MOBILE USA, INC. | 6529 | DAYTON | OH |
| — | 937-829 | not yet reported which blocks → | T-MOBILE USA, INC. | 6529 | DAYTON | OH |
| — | 937-830 | 4XXX8XXX which blocks → | T-MOBILE USA, INC. | 6529 | DAYTON | OH |
| — | 937-831 | 2XXX3XXX4XXX5XXX7XXX8XXX which blocks → | T-MOBILE USA, INC. | 6529 | SPRINGFLD | OH |
| — | 937-838 | 2XXX3XXX4XXX5XXX7XXX8XXX which blocks → | T-MOBILE USA, INC. | 6529 | DAYTON | OH |
| — | 937-869 | 1XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 3 holders which blocks → | T-MOBILE USA, INC. | 6529 | URBANA | OH |
| — | 937-875 | 2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → | T-MOBILE USA, INC. | 6529 | TROY | OH |
Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/21/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.