NumberResearchThousands-blocks in 509-550
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 509-550 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 509 blocks
Most active assignees, all time — NPA 509
New assignments by month
Sep 2026
Aug 2026
Jul 2026
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2017-09-06 | 509-550-0XXX | 0000–0999 | Assigned | ONVOY, LLC - WA | 483E | NEWPORT | WA |
| 2018-10-01 | 509-550-1XXX | 1000–1999 | Assigned | T-MOBILE USA, INC. | 6529 | NEWPORT | WA |
| 2004-05-26 | 509-550-2XXX | 2000–2999 | Assigned | ONVOY, LLC - WA | 483E | NEWPORT | WA |
| 2022-04-18 | 509-550-3XXX | 3000–3999 | Assigned | T-MOBILE USA, INC. | 6529 | NEWPORT | WA |
| — | 509-550-4XXX | 4000–4999 | Available | NEWPORT | WA | ||
| 2016-02-04 | 509-550-5XXX | 5000–5999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - WA | 6121 | NEWPORT | WA |
| — | 509-550-6XXX | 6000–6999 | Available | NEWPORT | WA | ||
| 2007-09-27 | 509-550-7XXX | 7000–7999 | Assigned | ONVOY, LLC - WA | 483E | NEWPORT | WA |
| 2021-01-30 | 509-550-8XXX | 8000–8999 | Assigned | T-MOBILE USA, INC. | 6529 | NEWPORT | WA |
| — | 509-550-9XXX | 9000–9999 | Reserved | T-MOBILE USA, INC. | 6529 | NEWPORT | WA |
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.