NumberResearchThousands-blocks in 424-528
This prefix’s ten 1,000-number blocks and who holds each — 10 on record · from the daily NANPA thousands-block report, 09/20/2026
The ten 1,000-number thousand-blocks inside prefix 424-528 and who was initially assigned each. Under pooling these blocks often belong to different carriers — the single prefix-level “assignee” is usually just the pool / code holder, not who holds the numbers. ← all 424 blocks
Most active assignees, all time — NPA 424
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 |
|---|---|---|---|---|---|---|---|
| 2017-05-18 | 424-528-0XXX | 0000–0999 | Assigned | ONVOY, LLC - CA | 649C | CMTN GRDN | CA |
| 2017-05-22 | 424-528-1XXX | 1000–1999 | Assigned | TELNYX LLC | 073H | CMTN GRDN | CA |
| 2017-08-09 | 424-528-2XXX | 2000–2999 | Assigned | TWC IP ENABLED SERVICES, LLC | 793K | CMTN GRDN | CA |
| 2018-05-14 | 424-528-3XXX | 3000–3999 | Assigned | T-MOBILE USA, INC. | 6529 | CMTN GRDN | CA |
| 2018-05-14 | 424-528-4XXX | 4000–4999 | Assigned | T-MOBILE USA, INC. | 6529 | CMTN GRDN | CA |
| 2018-05-14 | 424-528-5XXX | 5000–5999 | Assigned | T-MOBILE USA, INC. | 6529 | CMTN GRDN | CA |
| 2017-03-20 | 424-528-6XXX | 6000–6999 | Assigned | TELEPORT COMMUNICATIONS AMERICA, LLC - CA | 7139 | CMTN GRDN | CA |
| 2018-05-14 | 424-528-7XXX | 7000–7999 | Assigned | T-MOBILE USA, INC. | 6529 | CMTN GRDN | CA |
| 2022-05-05 | 424-528-8XXX | 8000–8999 | Assigned | ONVOY SPECTRUM, LLC | 624H | CMTN GRDN | CA |
| 2018-05-14 | 424-528-9XXX | 9000–9999 | Assigned | T-MOBILE USA, INC. | 6529 | CMTN GRDN | 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.