NumberResearchThousands-blocks in 573-557
This prefix’s ten 1,000-number blocks and who holds each — 10 on record · from the daily NANPA thousands-block report, 09/19/2026
The ten 1,000-number thousand-blocks inside prefix 573-557 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
Aug 2026
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2013-11-01 | 573-557-0XXX | 0000–0999 | Assigned | IP HORIZON LLC | 515J | ELDON | MO |
| 2018-07-11 | 573-557-1XXX | 1000–1999 | Assigned | TELNYX LLC | 073H | ELDON | MO |
| 2007-06-26 | 573-557-2XXX | 2000–2999 | Assigned | CHARTER IP ENABLED SERVICES, LLC | 792K | ELDON | MO |
| 2002-05-09 | 573-557-3XXX | 3000–3999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - MO | 4932 | ELDON | MO |
| 2013-04-08 | 573-557-4XXX | 4000–4999 | Assigned | PEERLESS NETWORK OF MISSOURI, LLC - MO | 225F | ELDON | MO |
| 2011-08-19 | 573-557-5XXX | 5000–5999 | Assigned | BANDWIDTH.COM CLEC, LLC - MO | 993E | ELDON | MO |
| 2013-04-08 | 573-557-6XXX | 6000–6999 | Assigned | PEERLESS NETWORK OF MISSOURI, LLC - MO | 225F | ELDON | MO |
| 2025-02-17 | 573-557-7XXX | 7000–7999 | Assigned | T-MOBILE USA, INC. | 6529 | ELDON | MO |
| 2011-09-22 | 573-557-8XXX | 8000–8999 | Assigned | AT&T ENTERPRISES, LLC | 516C | ELDON | MO |
| 2008-12-19 | 573-557-9XXX | 9000–9999 | Assigned | BANDWIDTH.COM CLEC, LLC - MO | 993E | ELDON | MO |
Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/19/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.