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 858
New assignments by month
Sep 2026
Aug 2026
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2016-09-20 | 858-914-9XXX | 9000–9999 | Assigned | AT&T ENTERPRISES, LLC | 516C | RNCHOSANFE | CA |
| 2016-09-14 | 858-672-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | RNCHOPNQTS | CA |
| 2016-08-08 | 858-280-7XXX | 7000–7999 | Assigned | AT&T ENTERPRISES, LLC | 516C | DEL MAR | CA |
| 2016-05-18 | 858-757-9XXX | 9000–9999 | Assigned | AT&T ENTERPRISES, LLC | 516C | SNDG MRMS | CA |
| 2015-09-30 | 858-732-7XXX | 7000–7999 | Assigned | AT&T ENTERPRISES, LLC | 516C | LA JOLLA | CA |
| 2015-04-20 | 858-987-0XXX | 0000–0999 | Assigned | AT&T ENTERPRISES, LLC | 516C | SNDG LVTA | CA |
| 2014-09-04 | 858-291-8XXX | 8000–8999 | Assigned | AT&T ENTERPRISES, LLC | 516C | LA JOLLA | CA |
| 2012-01-13 | 858-798-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | RNCHOBRNDO | CA |
| 2011-08-23 | 858-230-7XXX | 7000–7999 | Assigned | AT&T ENTERPRISES, LLC | 516C | LA JOLLA | CA |
| 2011-05-05 | 858-430-6XXX | 6000–6999 | Assigned | AT&T ENTERPRISES, LLC | 516C | SNDG LVTA | CA |
| 2011-03-26 | 858-860-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | SNDG MRMS | CA |
| 2010-11-24 | 858-847-2XXX | 2000–2999 | Assigned | AT&T ENTERPRISES, LLC | 516C | DEL MAR | CA |
| 2010-03-25 | 858-886-7XXX | 7000–7999 | Assigned | AT&T ENTERPRISES, LLC | 516C | LA JOLLA | CA |
| 2008-03-18 | 858-668-7XXX | 7000–7999 | Assigned | AT&T ENTERPRISES, LLC | 516C | POWAY | CA |
| 2006-05-16 | 858-737-4XXX | 4000–4999 | Assigned | AT&T ENTERPRISES, LLC | 516C | SNDG LVTA | CA |
| 2006-05-15 | 858-352-6XXX | 6000–6999 | Assigned | AT&T ENTERPRISES, LLC | 516C | LA JOLLA | CA |
| 2006-03-10 | 858-365-7XXX | 7000–7999 | Assigned | AT&T ENTERPRISES, LLC | 516C | RNCHOPNQTS | CA |
| 2006-03-10 | 858-397-2XXX | 2000–2999 | Assigned | AT&T ENTERPRISES, LLC | 516C | SNDG MRMS | CA |
| 2006-03-10 | 858-524-6XXX | 6000–6999 | Assigned | AT&T ENTERPRISES, LLC | 516C | RNCHOBRNDO | CA |
| 2006-03-09 | 858-925-7XXX | 7000–7999 | Assigned | AT&T ENTERPRISES, LLC | 516C | DEL MAR | CA |
| 2004-11-05 | 858-771-1XXX | 1000–1999 | Assigned | AT&T ENTERPRISES, LLC | 516C | RNCHOSANFE | 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.