NumberResearchRecent thousands-block assignments
0 blocks assigned in the last 30 days · from the daily NANPA thousands-block report, 09/20/2026
Most carrier growth happens here, not at the prefix level: under number pooling, carriers receive individual 1,000-number blocks (e.g. 626-470-0XXX) within already-assigned prefixes. Assignments are initial assignments — the current serving carrier of individual numbers may differ due to portability.
Most active assignees, all time — NPA 831
New assignments by month
Sep 2026
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2024-10-08 | 831-778-3XXX | 3000–3999 | Assigned | AT&T ENTERPRISES, LLC | 516C | SAN LUCAS | CA |
| 2015-07-29 | 831-796-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | SALINAS | CA |
| 2015-07-16 | 831-226-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | SANTA CRUZ | CA |
| 2015-06-11 | 831-726-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | WATSONVL | CA |
| 2014-05-01 | 831-747-2XXX | 2000–2999 | Assigned | AT&T ENTERPRISES, LLC | 516C | MONTEREY | CA |
| 2014-01-28 | 831-272-6XXX | 6000–6999 | Assigned | AT&T ENTERPRISES, LLC | 516C | SALINAS | CA |
| 2012-11-07 | 831-652-3XXX | 3000–3999 | Assigned | AT&T ENTERPRISES, LLC | 516C | CARMEL VLY | CA |
| 2011-09-14 | 831-217-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | BOULDERCRK | CA |
| 2011-09-14 | 831-290-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | GONZALES | CA |
| 2011-09-14 | 831-508-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | FELTON | CA |
| 2011-09-14 | 831-525-8XXX | 8000–8999 | Assigned | AT&T ENTERPRISES, LLC | 516C | KING CITY | CA |
| 2011-09-14 | 831-532-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | BEN LOMOND | CA |
| 2011-09-14 | 831-593-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | SAN JUAN | CA |
| 2011-09-14 | 831-627-4XXX | 4000–4999 | Assigned | AT&T ENTERPRISES, LLC | 516C | SAN ARDO | CA |
| 2011-09-14 | 831-628-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | TRES PINOS | CA |
| 2011-07-26 | 831-232-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | CHUALAR | CA |
| 2011-06-08 | 831-237-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | SOLEDAD | CA |
| 2011-01-25 | 831-453-7XXX | 7000–7999 | Assigned | AT&T ENTERPRISES, LLC | 516C | CASTROVL | CA |
| 2010-10-26 | 831-856-8XXX | 8000–8999 | Assigned | AT&T ENTERPRISES, LLC | 516C | GREENFIELD | CA |
| 2009-12-14 | 831-249-7XXX | 7000–7999 | Assigned | AT&T ENTERPRISES, LLC | 516C | BIG SUR | CA |
| 2008-08-05 | 831-708-4XXX | 4000–4999 | Assigned | AT&T ENTERPRISES, LLC | 516C | APTOS | CA |
| 2008-05-07 | 831-272-3XXX | 3000–3999 | Assigned | AT&T ENTERPRISES, LLC | 516C | SALINAS | CA |
| 2008-05-07 | 831-574-3XXX | 3000–3999 | Assigned | AT&T ENTERPRISES, LLC | 516C | CARMEL | CA |
| 2008-04-03 | 831-265-7XXX | 7000–7999 | Assigned | AT&T ENTERPRISES, LLC | 516C | HOLLISTER | CA |
| 2006-10-19 | 831-536-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | WATSONVL | CA |
| 2006-06-12 | 831-515-7XXX | 7000–7999 | Assigned | AT&T ENTERPRISES, LLC | 516C | SANTA CRUZ | CA |
| 2005-04-08 | 831-747-1XXX | 1000–1999 | Assigned | AT&T ENTERPRISES, LLC | 516C | MONTEREY | CA |
Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/20/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.