NumberResearch Membership · Data 09/20/2026

Recent thousands-block assignments

11 blocks assigned in the last 30 days · from the daily NANPA thousands-block report, 09/20/2026

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 331
ONVOY, LLC 6
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 3
NEW CINGULAR WIRELESS PCS, LLC - IL 1
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
2010-07-02 331-642-3XXX 3000–3999Assigned T-MOBILE USA, INC. 6529 ELMHURST IL
2010-07-02 331-642-4XXX 4000–4999Assigned T-MOBILE USA, INC. 6529 ELMHURST IL
2010-07-02 331-642-5XXX 5000–5999Assigned T-MOBILE USA, INC. 6529 ELMHURST IL
2010-06-25 331-223-6XXX 6000–6999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 ST CHARLES IL
2010-06-22 331-222-4XXX 4000–4999Assigned ONVOY, LLC 224C ST CHARLES IL
2010-06-22 331-222-5XXX 5000–5999Assigned ONVOY, LLC 224C ST CHARLES IL
2010-06-22 331-333-1XXX 1000–1999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E NAPERVILLE IL
2010-06-22 331-333-3XXX 3000–3999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E NAPERVILLE IL
2010-06-22 331-551-7XXX 7000–7999Assigned ONVOY, LLC 224C LOMBARD IL
2010-06-21 331-625-2XXX 2000–2999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 DOWNERSGRV IL
2010-06-10 331-431-4XXX 4000–4999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E AURORA IL
2010-06-10 331-431-5XXX 5000–5999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E AURORA IL
2010-06-10 331-431-6XXX 6000–6999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E AURORA IL
2010-06-10 331-457-2XXX 2000–2999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 NAPERVILLE IL
2010-06-07 331-431-2XXX 2000–2999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 AURORA IL
2010-06-07 331-431-3XXX 3000–3999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 AURORA IL
2010-06-01 331-223-5XXX 5000–5999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ST CHARLES IL
2010-06-01 331-333-2XXX 2000–2999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 NAPERVILLE IL
2010-06-01 331-457-1XXX 1000–1999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 NAPERVILLE IL
2010-06-01 331-625-9XXX 9000–9999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 DOWNERSGRV IL
2010-05-27 331-222-3XXX 3000–3999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E ST CHARLES IL
2010-05-27 331-330-8XXX 8000–8999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E NAPERVILLE IL
2010-05-27 331-551-6XXX 6000–6999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E LOMBARD IL
2010-05-06 331-222-2XXX 2000–2999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ST CHARLES IL
2010-04-27 331-454-4XXX 4000–4999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2010-04-27 331-575-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2010-04-27 331-575-8XXX 8000–8999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2010-04-27 331-643-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2010-04-27 331-643-8XXX 8000–8999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2010-04-09 331-462-0XXX 0000–0999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E LOMBARD IL
2010-03-29 331-425-8XXX 8000–8999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E AURORA IL
2010-03-29 331-625-1XXX 1000–1999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E DOWNERSGRV IL
2010-03-19 331-330-7XXX 7000–7999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E NAPERVILLE IL
2010-03-19 331-642-1XXX 1000–1999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E ELMHURST IL
2010-03-10 331-642-6XXX 6000–6999Assigned FIRST COMMUNICATIONS, LLC 460K ELMHURST IL
2010-03-04 331-457-6XXX 6000–6999Assigned FIRST COMMUNICATIONS, LLC 460K NAPERVILLE IL
2010-02-23 331-454-2XXX 2000–2999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 AURORA IL
2010-02-23 331-454-3XXX 3000–3999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 AURORA IL
2010-02-22 331-330-5XXX 5000–5999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 NAPERVILLE IL
2010-02-22 331-330-6XXX 6000–6999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 NAPERVILLE IL
2010-02-22 331-333-4XXX 4000–4999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC - IL 7196 NAPERVILLE IL
2010-02-16 331-588-2XXX 2000–2999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ST CHARLES IL
2010-02-16 331-588-9XXX 9000–9999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ST CHARLES IL
2010-02-12 331-481-5XXX 5000–5999Assigned ONVOY, LLC 224C DOWNERSGRV IL
2010-02-11 331-330-4XXX 4000–4999Assigned LEVEL 3 COMMUNICATIONS, LLC - IL 6115 NAPERVILLE IL
2010-02-11 331-725-8XXX 8000–8999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 OSWEGO IL
2010-02-10 331-725-7XXX 7000–7999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E OSWEGO IL
2010-02-03 331-465-1XXX 1000–1999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E W CHICAGO IL
2010-01-26 331-330-3XXX 3000–3999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 NAPERVILLE IL
2009-12-30 331-551-5XXX 5000–5999Assigned FIRST COMMUNICATIONS, LLC 460K LOMBARD IL

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.