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 517
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| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2011-09-29 | 517-443-4XXX | 4000–4999 | Assigned | TC3 TELECOM, INC. - MI | 3459 | OGDEN CTR | MI |
| 2010-12-21 | 517-467-1XXX | 1000–1999 | Assigned | TC3 TELECOM, INC. - MI | 3459 | ONSTED | MI |
| 2010-11-02 | 517-436-1XXX | 1000–1999 | Assigned | TC3 TELECOM, INC. - MI | 3459 | SAND CREEK | MI |
| 2010-10-29 | 517-447-6XXX | 6000–6999 | Assigned | TC3 TELECOM, INC. - MI | 3459 | DEERFIELD | MI |
| 2010-10-08 | 517-431-6XXX | 6000–6999 | Assigned | TC3 TELECOM, INC. - MI | 3459 | TIPTON | MI |
| 2010-10-06 | 517-451-6XXX | 6000–6999 | Assigned | TC3 TELECOM, INC. - MI | 3459 | BRITTON | MI |
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.