NumberResearchThousands-blocks in 443-364
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 443-364 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 443 blocks
Most active assignees, all time — NPA 443
New assignments by month
Sep 2026
Aug 2026
Jul 2026
Jun 2026
May 2026
Apr 2026
Mar 2026
Feb 2026
Jan 2026
Dec 2025
Nov 2025
Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2018-07-30 | 443-364-0XXX | 0000–0999 | Assigned | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | ELLICOTTCY | MD |
| 2018-04-05 | 443-364-1XXX | 1000–1999 | Assigned | METROPCS, INC. | 5562 | ELLICOTTCY | MD |
| 2007-05-11 | 443-364-2XXX | 2000–2999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - MD | 6119 | ELLICOTTCY | MD |
| 2012-02-06 | 443-364-3XXX | 3000–3999 | Assigned | ONVOY, LLC - MD | 876D | ELLICOTTCY | MD |
| 2008-06-26 | 443-364-4XXX | 4000–4999 | Assigned | YMAX COMMUNICATIONS CORP. - MD | 281E | ELLICOTTCY | MD |
| — | 443-364-5XXX | 5000–5999 | Reserved | TELEPORT COMMUNICATIONS AMERICA, LLC - MD | 7325 | ELLICOTTCY | MD |
| 2009-01-30 | 443-364-6XXX | 6000–6999 | Assigned | YMAX COMMUNICATIONS CORP. - MD | 281E | ELLICOTTCY | MD |
| 2009-01-30 | 443-364-7XXX | 7000–7999 | Assigned | YMAX COMMUNICATIONS CORP. - MD | 281E | ELLICOTTCY | MD |
| 2008-11-12 | 443-364-8XXX | 8000–8999 | Assigned | BANDWIDTH.COM CLEC, LLC - MD | 071F | ELLICOTTCY | MD |
| 2007-07-17 | 443-364-9XXX | 9000–9999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - MD | 6119 | ELLICOTTCY | MD |
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.