NumberResearchRecent prefix assignments
0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/19/2026
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 |
|---|---|---|---|---|---|---|
| 2017-01-31 | 857-287 | 0–9 XXXall 10 · 3 holders which blocks → | METROPCS, INC. | 5562 | BOSTON | MA |
| 2016-09-21 | 857-505 | 0–9 XXXall 10 · 4 holders which blocks → | METROPCS, INC. | 5562 | BOSTON | MA |
| 2016-09-12 | 857-773 | 0XXX1XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → | METROPCS, INC. | 5562 | JAMAICA PL | MA |
| 2016-07-18 | 857-762 | 0–9 XXXall 10 · 3 holders which blocks → | METROPCS, INC. | 5562 | BOSTON | MA |
| 2011-02-22 | 857-261 | 0–9 XXXwhole prefix which blocks → | METROPCS, INC. | 5562 | BOSTON | MA |
| 2010-06-25 | 857-258 | 0–9 XXXwhole prefix which blocks → | METROPCS, INC. | 5562 | BOSTON | MA |
| 2010-06-10 | 857-266 | 0–9 XXXwhole prefix which blocks → | METROPCS, INC. | 5562 | BOSTON | MA |
| 2009-06-11 | 857-615 | 0–9 XXXwhole prefix which blocks → | METROPCS, INC. | 5562 | BOSTON | MA |
| 2009-06-08 | 857-237 | 0–9 XXXwhole prefix which blocks → | METROPCS, INC. | 5562 | BOSTON | MA |
| 2009-06-08 | 857-247 | 0–9 XXXwhole prefix which blocks → | METROPCS, INC. | 5562 | BOSTON | MA |
| 2008-08-04 | 857-236 | 0–9 XXXwhole prefix which blocks → | METROPCS, INC. | 5562 | BOSTON | MA |
| 2008-08-04 | 857-249 | 0–9 XXXwhole prefix which blocks → | METROPCS, INC. | 5562 | BOSTON | MA |
| 2008-08-04 | 857-251 | 0–9 XXXwhole prefix which blocks → | METROPCS, INC. | 5562 | BOSTON | MA |
| 2008-08-04 | 857-312 | 0–9 XXXwhole prefix which blocks → | METROPCS, INC. | 5562 | BOSTON | MA |
| 2008-08-04 | 857-417 | 0–9 XXXwhole prefix which blocks → | METROPCS, INC. | 5562 | BOSTON | MA |
| 2005-05-25 | 857-221 | 0–9 XXXall 10 · 4 holders which blocks → | METROPCS, INC. | 5562 | BOSTON | MA |
| 2002-10-28 | 857-201 | 0XXX2XXX3XXX4XXX5XXX7XXX8XXX · 4 holders which blocks → | METROPCS, INC. | 5562 | WINTHROP | MA |
| 2002-07-30 | 857-231 | 4XXX5XXX7XXX8XXX9XXX · 3 holders which blocks → | METROPCS, INC. | 5562 | NEWTON | MA |
| 2002-07-30 | 857-526 | 8XXX9XXX · 2 holders which blocks → | METROPCS, INC. | 5562 | QUINCY | MA |
| 2002-07-30 | 857-719 | 0XXX which blocks → | METROPCS, INC. | 5562 | JAMAICA PL | MA |
| 2002-07-30 | 857-888 | none assigned yet which blocks → | METROPCS, INC. | 5562 | EVERETT | MA |
| 2001-06-29 | 857-217 | 1XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | METROPCS, INC. | 5562 | DORCHESTER | MA |
| 2001-04-23 | 857-212 | none assigned yet which blocks → | METROPCS, INC. | 5562 | DORCHESTER | MA |
| 2001-04-20 | 857-257 | 8XXX which blocks → | METROPCS, INC. | 5562 | SO BOSTON | MA |
| — | 857-246 | 0–9 XXXall 10 · 4 holders which blocks → | METROPCS, INC. | 5562 | BOSTON | MA |
Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/19/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.