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 |
|---|---|---|---|---|---|---|
| 2017-03-27 | 972-990 | 0–9 XXXwhole prefix which blocks → | SOUTHWESTERN BELL TELEPHONE COMPANY - TX | 7726 | IRVING | TX |
| 2016-07-21 | 972-817 | 0–9 XXXwhole prefix which blocks → | SOUTHWESTERN BELL TELEPHONE COMPANY - TX | 7726 | IRVING | TX |
| 2002-10-23 | 972-526 | 0–9 XXXall 10 · 2 holders which blocks → | SOUTHWESTERN BELL TELEPHONE COMPANY - TX | 7726 | PLANO | TX |
| — | 972-309 | 3XXX9XXX · 2 holders which blocks → | SOUTHWESTERN BELL TELEPHONE COMPANY - TX | 7726 | PLANO | TX |
| — | 972-312 | 2XXX3XXX4XXX5XXX6XXX7XXX · 2 holders which blocks → | SOUTHWESTERN BELL TELEPHONE COMPANY - TX | 7726 | PLANO | TX |
| — | 972-398 | not yet reported which blocks → | SOUTHWESTERN BELL TELEPHONE COMPANY - TX | 7726 | PLANO | TX |
| — | 972-583 | 5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → | SOUTHWESTERN BELL TELEPHONE COMPANY - TX | 7726 | PLANO | TX |
| — | 972-673 | 9XXX which blocks → | SOUTHWESTERN BELL TELEPHONE COMPANY - TX | 7726 | PLANO | TX |
| — | 972-801 | 7XXX8XXX which blocks → | SOUTHWESTERN BELL TELEPHONE COMPANY - TX | 7726 | PLANO | TX |
| — | 972-820 | 1XXX which blocks → | SOUTHWESTERN BELL TELEPHONE COMPANY - TX | 7726 | CARROLLTON | TX |
| — | 972-870 | not yet reported which blocks → | SOUTHWESTERN BELL TELEPHONE COMPANY - TX | 7726 | IRVING | TX |
| — | 972-871 | not yet reported which blocks → | SOUTHWESTERN BELL TELEPHONE COMPANY - TX | 7726 | IRVING | TX |
| — | 972-906 | 8XXX which blocks → | SOUTHWESTERN BELL TELEPHONE COMPANY - TX | 7726 | LEWISVILLE | TX |
| — | 972-943 | not yet reported which blocks → | SOUTHWESTERN BELL TELEPHONE COMPANY - TX | 7726 | PLANO | TX |
| — | 972-953 | 5XXX6XXX7XXX8XXX9XXX which blocks → | SOUTHWESTERN BELL TELEPHONE COMPANY - TX | 7726 | IRVING | TX |
| — | 972-956 | not yet reported which blocks → | SOUTHWESTERN BELL TELEPHONE COMPANY - TX | 7726 | LEWISVILLE | TX |
| — | 972-983 | 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX which blocks → | SOUTHWESTERN BELL TELEPHONE COMPANY - TX | 7726 | IRVING | TX |
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.