NumberResearch Membership · Data 09/21/2026

Recent thousands-block assignments

0 blocks assigned in the last 30 days · from the daily NANPA thousands-block report, 09/21/2026

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

Most carrier growth happens here, not at the prefix level: under number pooling, carriers receive individual 1,000-number blocks (e.g. 626-470-0XXX) within already-assigned prefixes. Assignments are initial assignments — the current serving carrier of individual numbers may differ due to portability.

Most active assignees, all time — NPA 321
MCI WORLDCOM COMMUNICATIONS, INC. - FL 98
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
2021-04-16 321-399-6XXX 6000–6999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 COCOABEACH FL
2021-01-05 321-510-3XXX 3000–3999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 EAU GALLIE FL
2014-09-02 321-233-8XXX 8000–8999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 SANFORD FL
2014-07-07 321-233-7XXX 7000–7999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 SANFORD FL
2012-03-19 321-888-2XXX 2000–2999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 ORLANDO FL
2012-03-19 321-888-3XXX 3000–3999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 ORLANDO FL
2012-03-19 321-888-4XXX 4000–4999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 ORLANDO FL
2011-11-30 321-400-1XXX 1000–1999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 ORLANDO FL
2011-11-02 321-578-5XXX 5000–5999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 SANFORD FL
2011-04-06 321-216-2XXX 2000–2999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 MELBOURNE FL
2010-12-07 321-608-2XXX 2000–2999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 MELBOURNE FL
2010-12-06 321-401-9XXX 9000–9999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 WKISSIMMEE FL
2010-10-22 321-400-5XXX 5000–5999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 ORLANDO FL
2010-10-22 321-400-6XXX 6000–6999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 ORLANDO FL
2010-09-28 321-295-5XXX 5000–5999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 WINTERPARK FL
2009-08-05 321-286-8XXX 8000–8999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 WKISSIMMEE FL
2009-04-06 321-682-2XXX 2000–2999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 KISSIMMEE FL
2008-10-31 321-549-5XXX 5000–5999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 MELBOURNE FL
2008-10-31 321-549-6XXX 6000–6999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 MELBOURNE FL
2008-10-03 321-304-4XXX 4000–4999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 WINTERPARK FL
2008-10-03 321-304-5XXX 5000–5999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 WINTERPARK FL
2008-09-02 321-250-4XXX 4000–4999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 KISSIMMEE FL
2008-05-20 321-395-3XXX 3000–3999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 LKBUNAVIST FL
2008-01-28 321-445-7XXX 7000–7999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 ORLANDO FL
2007-04-10 321-765-5XXX 5000–5999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 OVIEDO FL
2007-04-10 321-765-6XXX 6000–6999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 OVIEDO FL
2007-01-18 321-745-6XXX 6000–6999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 COCOA FL
2006-12-14 321-329-2XXX 2000–2999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 REEDYCREEK FL
2006-11-15 321-445-4XXX 4000–4999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 ORLANDO FL
2006-11-15 321-445-5XXX 5000–5999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 ORLANDO FL
2006-11-15 321-445-6XXX 6000–6999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 ORLANDO FL
2006-09-22 321-574-4XXX 4000–4999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 MELBOURNE FL
2006-09-22 321-775-6XXX 6000–6999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 EAU GALLIE FL
2006-09-22 321-821-3XXX 3000–3999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 MELBOURNE FL
2006-09-13 321-283-5XXX 5000–5999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 SANFORD FL
2006-07-18 321-275-4XXX 4000–4999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 SANFORD FL
2006-07-18 321-275-5XXX 5000–5999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 SANFORD FL
2006-07-18 321-296-6XXX 6000–6999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 OVIEDO FL
2006-07-18 321-296-7XXX 7000–7999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 OVIEDO FL
2006-06-22 321-250-7XXX 7000–7999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 KISSIMMEE FL
2006-06-22 321-250-8XXX 8000–8999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 KISSIMMEE FL
2006-06-22 321-697-7XXX 7000–7999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 KISSIMMEE FL
2006-06-15 321-332-9XXX 9000–9999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 ORLANDO FL
2006-01-27 321-549-4XXX 4000–4999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 MELBOURNE FL
2006-01-16 321-745-2XXX 2000–2999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 COCOA FL
2005-11-21 321-348-3XXX 3000–3999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 OVIEDO FL
2005-11-11 321-373-1XXX 1000–1999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 MELBOURNE FL
2005-11-11 321-549-3XXX 3000–3999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 MELBOURNE FL
2005-09-16 321-289-4XXX 4000–4999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 TITUSVILLE FL
2005-08-31 321-558-1XXX 1000–1999Assigned MCI WORLDCOM COMMUNICATIONS, INC. - FL 7448 ORLANDO FL

Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/21/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.