NumberResearch Membership · Data 09/21/2026

Recent thousands-block assignments

1 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, last 30 days — NPA 312
BANDWIDTH.COM CLEC, LLC - IL 1
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
2005-07-08 312-731-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2005-07-06 312-212-4XXX 4000–4999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 CHICGOZN01 IL
2005-07-06 312-212-5XXX 5000–5999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 CHICGOZN01 IL
2005-07-06 312-212-7XXX 7000–7999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 CHICGOZN01 IL
2005-06-14 312-731-5XXX 5000–5999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2005-06-14 312-731-6XXX 6000–6999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2005-05-26 312-523-0XXX 0000–0999Assigned PAETEC ITEL, LLC 829J CHICGOZN01 IL
2005-05-26 312-523-2XXX 2000–2999Assigned PAETEC ITEL, LLC 829J CHICGOZN01 IL
2005-05-25 312-753-8XXX 8000–8999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2005-05-25 312-753-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2005-05-25 312-863-1XXX 1000–1999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2005-05-25 312-863-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2005-05-13 312-529-4XXX 4000–4999Assigned FIRST COMMUNICATIONS, LLC 460K CHICGOZN01 IL
2005-04-25 312-285-2XXX 2000–2999Assigned AT&T ENTERPRISES, LLC 516C CHICGOZN01 IL
2005-03-21 312-529-5XXX 5000–5999Assigned FIRST COMMUNICATIONS, LLC 460K CHICGOZN01 IL
2005-03-04 312-799-0XXX 0000–0999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2005-03-03 312-267-0XXX 0000–0999Assigned LEVEL 3 COMMUNICATIONS, LLC - IL 6115 CHICGOZN01 IL
2005-03-03 312-533-4XXX 4000–4999Assigned LEVEL 3 COMMUNICATIONS, LLC - IL 6115 CHICGOZN01 IL
2005-03-03 312-546-3XXX 3000–3999Assigned LEVEL 3 COMMUNICATIONS, LLC - IL 6115 CHICGOZN01 IL
2005-03-03 312-546-6XXX 6000–6999Assigned LEVEL 3 COMMUNICATIONS, LLC - IL 6115 CHICGOZN01 IL
2005-02-22 312-730-8XXX 8000–8999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2005-01-26 312-379-3XXX 3000–3999Assigned FIRST COMMUNICATIONS, LLC 460K CHICGOZN01 IL
2005-01-26 312-768-7XXX 7000–7999Assigned FIRST COMMUNICATIONS, LLC 460K CHICGOZN01 IL
2005-01-06 312-794-7XXX 7000–7999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 CHICGOZN01 IL
2005-01-06 312-794-8XXX 8000–8999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 CHICGOZN01 IL
2004-12-29 312-324-0XXX 0000–0999Assigned LEVEL 3 COMMUNICATIONS, LLC - IL 6115 CHICGOZN01 IL
2004-12-29 312-324-3XXX 3000–3999Assigned LEVEL 3 COMMUNICATIONS, LLC - IL 6115 CHICGOZN01 IL
2004-12-16 312-506-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2004-12-10 312-753-6XXX 6000–6999Assigned PAETEC ITEL, LLC 829J CHICGOZN01 IL
2004-12-10 312-753-7XXX 7000–7999Assigned PAETEC ITEL, LLC 829J CHICGOZN01 IL
2004-12-03 312-799-1XXX 1000–1999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2004-12-03 312-799-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2004-11-08 312-604-4XXX 4000–4999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 CHICGOZN01 IL
2004-11-08 312-650-7XXX 7000–7999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 CHICGOZN01 IL
2004-11-08 312-650-8XXX 8000–8999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 CHICGOZN01 IL
2004-11-05 312-731-3XXX 3000–3999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2004-11-05 312-731-4XXX 4000–4999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2004-10-21 312-752-0XXX 0000–0999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2004-10-21 312-752-8XXX 8000–8999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2004-10-13 312-239-0XXX 0000–0999Assigned LEVEL 3 COMMUNICATIONS, LLC - IL 6115 CHICGOZN01 IL
2004-10-12 312-546-5XXX 5000–5999Assigned FIRST COMMUNICATIONS, LLC 460K CHICGOZN01 IL
2004-09-07 312-469-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2004-08-31 312-267-4XXX 4000–4999Assigned FIRST COMMUNICATIONS, LLC 460K CHICGOZN01 IL
2004-08-31 312-752-5XXX 5000–5999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2004-08-31 312-752-6XXX 6000–6999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2004-08-31 312-752-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2004-08-22 312-376-5XXX 5000–5999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2004-08-22 312-376-6XXX 6000–6999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2004-08-22 312-376-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 CHICGOZN01 IL
2004-08-21 312-376-8XXX 8000–8999Assigned LEVEL 3 COMMUNICATIONS, LLC - IL 6115 CHICGOZN01 IL

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.