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 |
|---|---|---|---|---|---|---|
| 2018-06-14 | 563-227 | 0–9 XXXall 10 · 6 holders which blocks → | MCC TELEPHONY OF IOWA, LLC - IA | 751F | DUBUQUE | IA |
| 2016-09-23 | 563-239 | 0–9 XXXall 10 · 7 holders which blocks → | MCC TELEPHONY OF IOWA, LLC - IA | 751F | DUBUQUE | IA |
| 2010-03-09 | 563-729 | 1XXX which blocks → | MCC TELEPHONY OF IOWA, LLC - IA | 751F | LE CLAIRE | IA |
| 2010-03-08 | 563-308 | 1XXX2XXX9XXX · 3 holders which blocks → | MCC TELEPHONY OF IOWA, LLC - IA | 751F | PRESTON | IA |
| 2010-02-16 | 563-424 | 0–9 XXXall 10 · 6 holders which blocks → | MCC TELEPHONY OF IOWA, LLC - IA | 751F | DAVENPORT | IA |
| 2007-03-16 | 563-223 | 0XXX2XXX3XXX4XXX7XXX8XXX9XXX · 5 holders which blocks → | MCC TELEPHONY OF IOWA, LLC - IA | 751F | ELDRIDGE | IA |
| 2007-03-16 | 563-694 | 8XXX which blocks → | MCC TELEPHONY OF IOWA, LLC - IA | 751F | GOOSE LAKE | IA |
| 2007-03-16 | 563-849 | 8XXX9XXX · 2 holders which blocks → | MCC TELEPHONY OF IOWA, LLC - IA | 751F | HESPER | IA |
| 2007-03-16 | 563-934 | 0XXX2XXX5XXX6XXX8XXX · 5 holders which blocks → | MCC TELEPHONY OF IOWA, LLC - IA | 751F | MILES | IA |
| 2007-02-04 | 563-651 | none assigned yet which blocks → | MCC TELEPHONY OF IOWA, LLC - IA | 751F | OXFORD JCT | IA |
| 2006-07-27 | 563-220 | 0XXX1XXX2XXX3XXX4XXX5XXX7XXX9XXX · 6 holders which blocks → | MCC TELEPHONY OF IOWA, LLC - IA | 751F | SABULA | IA |
| — | 563-486 | 0XXX2XXX · 2 holders which blocks → | MCC TELEPHONY OF IOWA, LLC - IA | 751F | OXFORD JCT | IA |
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.