NumberResearchThousands-blocks in 508-921
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 508-921 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 508 blocks
Most active assignees, all time — NPA 508
New assignments by month
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2008-11-10 | 508-921-0XXX | 0000–0999 | Assigned | BANDWIDTH.COM CLEC, LLC - MA | 990E | WALPOLE | MA |
| 2006-05-02 | 508-921-1XXX | 1000–1999 | Assigned | PAETEC ITEL, LLC | 829J | WALPOLE | MA |
| 2021-12-08 | 508-921-2XXX | 2000–2999 | Assigned | ONVOY SPECTRUM, LLC | 624H | WALPOLE | MA |
| 2007-01-11 | 508-921-3XXX | 3000–3999 | Assigned | COMCAST IP PHONE, LLC | 318J | WALPOLE | MA |
| 2004-01-09 | 508-921-4XXX | 4000–4999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - MA | 4018 | WALPOLE | MA |
| 2021-12-08 | 508-921-5XXX | 5000–5999 | Assigned | ONVOY SPECTRUM, LLC | 624H | WALPOLE | MA |
| 2005-03-22 | 508-921-6XXX | 6000–6999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - MA | 4018 | WALPOLE | MA |
| 2005-03-22 | 508-921-7XXX | 7000–7999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - MA | 4018 | WALPOLE | MA |
| 2009-11-04 | 508-921-8XXX | 8000–8999 | Assigned | YMAX COMMUNICATIONS CORP. - MA | 316E | WALPOLE | MA |
| 2008-02-08 | 508-921-9XXX | 9000–9999 | Assigned | YMAX COMMUNICATIONS CORP. - MA | 316E | WALPOLE | MA |
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.