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 |
|---|---|---|---|---|---|---|
| 2005-02-18 | 831-585 | 0–9 XXXall 10 · 3 holders which blocks → | METROPCS, INC. | 5562 | SALINAS | CA |
| 2001-09-13 | 831-383 | 5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | METROPCS, INC. | 5562 | MONTEREY | CA |
| 2001-09-13 | 831-794 | 5XXX6XXX7XXX8XXX9XXX which blocks → | METROPCS, INC. | 5562 | SALINAS | CA |
| 2001-07-12 | 831-776 | 0XXX4XXX5XXX6XXX7XXX8XXX which blocks → | METROPCS, INC. | 5562 | SALINAS | CA |
| 2001-07-12 | 831-869 | 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 2 holders which blocks → | METROPCS, INC. | 5562 | MONTEREY | CA |
| 2001-04-25 | 831-325 | 0XXX2XXX · 2 holders which blocks → | METROPCS, INC. | 5562 | SANTA CRUZ | CA |
| — | 831-212 | 2XXX3XXX which blocks → | METROPCS, INC. | 5562 | SANTA CRUZ | CA |
| — | 831-428 | 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX · 5 holders which blocks → | METROPCS, INC. | 5562 | SANTA CRUZ | CA |
| — | 831-500 | 0–9 XXXall 10 · 4 holders which blocks → | METROPCS, INC. | 5562 | SALINAS | CA |
| — | 831-760 | 1XXX3XXX4XXX5XXX8XXX9XXX which blocks → | METROPCS, INC. | 5562 | MONTEREY | CA |
| — | 831-774 | 0–9 XXXall 10 · 4 holders which blocks → | METROPCS, INC. | 5562 | GONZALES | CA |
| — | 831-785 | 0XXX1XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | METROPCS, INC. | 5562 | SALINAS | CA |
| — | 831-902 | 1XXX2XXX3XXX4XXX8XXX9XXX · 4 holders which blocks → | METROPCS, INC. | 5562 | HOLLISTER | CA |
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.