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 |
|---|---|---|---|---|---|---|
| — | 857-412 | 0–9 XXXall 10 · 2 holders which blocks → | ONVOY, LLC - MA | 892D | CAMBRIDGE | MA |
| — | 857-414 | 0–9 XXXall 10 · 3 holders which blocks → | HD CARRIER LLC | 321J | BRIGHTON | MA |
| — | 857-432 | not yet reported which blocks → | OMNIPOINT MIAMI E LICENSE, LLC | 6889 | BROOKLINE | MA |
| — | 857-452 | 0XXX1XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 2 holders which blocks → | OMNIPOINT MIAMI E LICENSE, LLC | 6889 | CHARLESTN | MA |
| — | 857-504 | 0–9 XXXall 10 · 6 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - MA | 4018 | BOSTON | MA |
| — | 857-511 | not yet reported which blocks → | MULTIPLE OCN LISTING | MULT | XXXXXXXXXX | MA |
| — | 857-520 | 0XXX1XXX2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 5 holders which blocks → | ONVOY, LLC - MA | 892D | HYDE PARK | MA |
| — | 857-540 | 4XXX5XXX7XXX8XXX · 2 holders which blocks → | OMNIPOINT MIAMI E LICENSE, LLC | 6889 | BRIGHTON | MA |
| — | 857-554 | not yet reported which blocks → | VERIZON NEW ENGLAND INC. | 9102 | XXXXXXXXXX | MA |
| — | 857-555 | not yet reported which blocks → | MULTIPLE OCN LISTING | MULT | DIR ASST | MA |
| — | 857-576 | 1XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → | BANDWIDTH.COM CLEC, LLC - MA | 990E | BROOKLINE | MA |
| — | 857-587 | 0–9 XXXall 10 · 2 holders which blocks → | HD CARRIER LLC | 321J | DORCHESTER | MA |
| — | 857-611 | not yet reported which blocks → | MULTIPLE OCN LISTING | MULT | XXXXXXXXXX | MA |
| — | 857-617 | not yet reported which blocks → | MA | |||
| — | 857-663 | 0–9 XXXall 10 · 7 holders which blocks → | ONVOY, LLC - MA | 892D | DORCHESTER | MA |
| — | 857-700 | not yet reported which blocks → | MA | |||
| — | 857-706 | 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 8 holders which blocks → | LEVEL 3 COMMUNICATIONS, LLC - MA | 4018 | CAMBRIDGE | MA |
| — | 857-711 | not yet reported which blocks → | MULTIPLE OCN LISTING | MULT | XXXXXXXXXX | MA |
| — | 857-811 | not yet reported which blocks → | MULTIPLE OCN LISTING | MULT | XXXXXXXXXX | MA |
| — | 857-814 | not yet reported which blocks → | VERIZON NEW ENGLAND INC. | 9102 | XXXXXXXXXX | MA |
| — | 857-900 | not yet reported which blocks → | VERIZON NEW ENGLAND INC. | 9102 | XXXXXXXXXX | MA |
| — | 857-911 | not yet reported which blocks → | MULTIPLE OCN LISTING | MULT | XXXXXXXXXX | MA |
| — | 857-920 | not yet reported which blocks → | VERIZON NEW ENGLAND INC. | 9102 | CAMBRIDGE | MA |
| — | 857-931 | not yet reported which blocks → | VERIZON NEW ENGLAND INC. | 9102 | BOSTON | MA |
| — | 857-940 | not yet reported which blocks → | MA | |||
| — | 857-950 | not yet reported which blocks → | MA | |||
| — | 857-958 | not yet reported which blocks → | MA | |||
| — | 857-959 | not yet reported which blocks → | MA | |||
| — | 857-976 | not yet reported which blocks → | MA | |||
| — | 857-995 | 0–9 XXXall 10 · 7 holders which blocks → | ONVOY, LLC - MA | 892D | SOMERVILLE | MA |
| — | 857-996 | 0–9 XXXwhole prefix which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | BOSTON | MA |
| — | 857-997 | 1XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | HD CARRIER LLC | 321J | SOMERVILLE | MA |
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.