NumberResearchThousands-blocks in 573-566
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 573-566 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 573 blocks
Most active assignees, all time — NPA 573
New assignments by month
Sep 2026
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| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| — | 573-566-0XXX | 0000–0999 | Available | STOVER | MO | ||
| — | 573-566-1XXX | 1000–1999 | Available | STOVER | MO | ||
| — | 573-566-2XXX | 2000–2999 | Available | STOVER | MO | ||
| 2021-02-08 | 573-566-3XXX | 3000–3999 | Assigned | ONVOY, LLC - MO | 093F | STOVER | MO |
| — | 573-566-4XXX | 4000–4999 | Available | STOVER | MO | ||
| 2020-09-28 | 573-566-5XXX | 5000–5999 | Assigned | ONVOY, LLC - MO | 093F | STOVER | MO |
| 2020-08-27 | 573-566-6XXX | 6000–6999 | Assigned | FRACTEL, LLC | 965H | STOVER | MO |
| — | 573-566-7XXX | 7000–7999 | Available | STOVER | MO | ||
| 2020-02-03 | 573-566-8XXX | 8000–8999 | Assigned | BANDWIDTH.COM CLEC, LLC - MO | 993E | STOVER | MO |
| 2015-06-18 | 573-566-9XXX | 9000–9999 | Assigned | WINDSTREAM MISSOURI, INC. | 1885 | STOVER | MO |
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.