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 510
New assignments by month
Sep 2026
Aug 2026
Jul 2026
Jun 2026
May 2026
Apr 2026
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Dec 2025
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2017-11-29 | 510-855-0XXX | 0000–0999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | OKLD MN-PD | CA |
| 2017-11-29 | 510-855-1XXX | 1000–1999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | OKLD MN-PD | CA |
| 2017-11-29 | 510-855-2XXX | 2000–2999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | OKLD MN-PD | CA |
| 2017-11-29 | 510-855-3XXX | 3000–3999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | OKLD MN-PD | CA |
| 2017-11-29 | 510-855-4XXX | 4000–4999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | OKLD MN-PD | CA |
| 2017-11-29 | 510-855-5XXX | 5000–5999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | OKLD MN-PD | CA |
| 2017-11-29 | 510-855-6XXX | 6000–6999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | OKLD MN-PD | CA |
| 2009-06-02 | 510-221-5XXX | 5000–5999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | RICHMOND | CA |
| 2009-02-19 | 510-256-4XXX | 4000–4999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | CROCKETT | CA |
| 2009-02-19 | 510-327-6XXX | 6000–6999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | HRCUL-RODE | CA |
| 2009-02-19 | 510-371-7XXX | 7000–7999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | FRNK MAIN | CA |
| 2009-02-19 | 510-964-8XXX | 8000–8999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | ELSBR-PINL | CA |
| 2008-05-27 | 510-787-5XXX | 5000–5999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | CROCKETT | CA |
| 2006-05-03 | 510-274-6XXX | 6000–6999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | HAYWARD | CA |
| 2006-05-03 | 510-374-5XXX | 5000–5999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | RICHMOND | CA |
| 2006-05-03 | 510-457-7XXX | 7000–7999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | OKLD MN-PD | CA |
| 2006-05-03 | 510-474-7XXX | 7000–7999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | FRNK GRNLF | CA |
| 2006-05-03 | 510-488-7XXX | 7000–7999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | OKLD FRTVL | CA |
| 2006-05-03 | 510-492-3XXX | 3000–3999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | FRNK OLIVR | CA |
| 2006-05-03 | 510-564-3XXX | 3000–3999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | OKLD TRNID | CA |
| 2006-05-03 | 510-647-7XXX | 7000–7999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | OKLD BKLY | CA |
| 2006-05-03 | 510-764-7XXX | 7000–7999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | OKLD ALMD | CA |
| 2006-05-03 | 510-896-7XXX | 7000–7999 | Assigned | UTILITY TELECOM GROUP, LLC - CA | 9262 | FRNK MAIN | 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.