NumberResearch Membership · Data 09/20/2026

Thousands-blocks in 972-621

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

Full prefixes (NXX) Thousands-blocks (1,000-number pools)

The ten 1,000-number thousand-blocks inside prefix 972-621 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 972 blocks

Most active assignees, all time — NPA 972
FRONTIER SOUTHWEST INC DBA FRONTIER COMM OF TEXAS 8
METROPCS, INC. 2
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
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Recent thousands-block assignments
AssignedThousands-blockLast 4 digitsStatusAssigneeOCNRate centerState
— 972-621-0XXX 0000–0999Reserved FRONTIER SOUTHWEST INC DBA FRONTIER COMM OF TEXAS 4344 IRVING TX
2011-06-29 972-621-1XXX 1000–1999Assigned METROPCS, INC. 5562 IRVING TX
— 972-621-2XXX 2000–2999Reserved FRONTIER SOUTHWEST INC DBA FRONTIER COMM OF TEXAS 4344 IRVING TX
— 972-621-3XXX 3000–3999Reserved FRONTIER SOUTHWEST INC DBA FRONTIER COMM OF TEXAS 4344 IRVING TX
— 972-621-4XXX 4000–4999Reserved FRONTIER SOUTHWEST INC DBA FRONTIER COMM OF TEXAS 4344 IRVING TX
— 972-621-5XXX 5000–5999Reserved FRONTIER SOUTHWEST INC DBA FRONTIER COMM OF TEXAS 4344 IRVING TX
— 972-621-6XXX 6000–6999Reserved FRONTIER SOUTHWEST INC DBA FRONTIER COMM OF TEXAS 4344 IRVING TX
— 972-621-7XXX 7000–7999Reserved FRONTIER SOUTHWEST INC DBA FRONTIER COMM OF TEXAS 4344 IRVING TX
— 972-621-8XXX 8000–8999Reserved FRONTIER SOUTHWEST INC DBA FRONTIER COMM OF TEXAS 4344 IRVING TX
2011-06-29 972-621-9XXX 9000–9999Assigned METROPCS, INC. 5562 IRVING TX

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.