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
2015-02-17 331-308-5XXX 5000–5999Assigned T-MOBILE USA, INC. 6529 BARTLETT IL
2015-02-17 331-308-6XXX 6000–6999Assigned T-MOBILE USA, INC. 6529 BARTLETT IL
2015-02-10 331-801-9XXX 9000–9999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 DOWNERSGRV IL
2015-01-20 331-701-4XXX 4000–4999Assigned FIRST COMMUNICATIONS, LLC 460K NAPERVILLE IL
2015-01-12 331-276-3XXX 3000–3999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ST CHARLES IL
2015-01-12 331-276-4XXX 4000–4999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ST CHARLES IL
2014-12-30 331-310-0XXX 0000–0999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E BIG ROCK IL
2014-12-30 331-701-3XXX 3000–3999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC - IL 7196 NAPERVILLE IL
2014-12-29 331-308-0XXX 0000–0999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E BARTLETT IL
2014-12-29 331-308-1XXX 1000–1999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E BARTLETT IL
2014-12-29 331-308-2XXX 2000–2999Assigned BANDWIDTH.COM CLEC, LLC - IL 984E BARTLETT IL
2014-12-15 331-253-0XXX 0000–0999Assigned ONVOY, LLC 224C LEMONT IL
2014-12-15 331-253-1XXX 1000–1999Assigned ONVOY, LLC 224C LEMONT IL
2014-12-15 331-276-5XXX 5000–5999Assigned ONVOY, LLC 224C ST CHARLES IL
2014-12-15 331-276-6XXX 6000–6999Assigned ONVOY, LLC 224C ST CHARLES IL
2014-12-12 331-701-0XXX 0000–0999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 NAPERVILLE IL
2014-12-11 331-214-7XXX 7000–7999Assigned ONVOY, LLC 224C DOWNERSGRV IL
2014-12-11 331-214-8XXX 8000–8999Assigned ONVOY, LLC 224C DOWNERSGRV IL
2014-11-24 331-702-9XXX 9000–9999Assigned ONVOY, LLC 224C NAPERVILLE IL
2014-11-19 331-245-0XXX 0000–0999Assigned ONVOY, LLC 224C BARTLETT IL
2014-11-18 331-276-7XXX 7000–7999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ST CHARLES IL
2014-11-18 331-276-8XXX 8000–8999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ST CHARLES IL
2014-11-18 331-276-9XXX 9000–9999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ST CHARLES IL
2014-11-17 331-703-4XXX 4000–4999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 W CHICAGO IL
2014-11-17 331-703-5XXX 5000–5999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 W CHICAGO IL
2014-11-17 331-703-6XXX 6000–6999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 W CHICAGO IL
2014-11-10 331-276-0XXX 0000–0999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 ST CHARLES IL
2014-11-07 331-216-3XXX 3000–3999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 OSWEGO IL
2014-11-07 331-216-4XXX 4000–4999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 OSWEGO IL
2014-10-29 331-253-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 LEMONT IL
2014-10-27 331-245-1XXX 1000–1999Assigned ONVOY, LLC 224C BARTLETT IL
2014-10-27 331-245-3XXX 3000–3999Assigned ONVOY, LLC 224C BARTLETT IL
2014-10-23 331-903-7XXX 7000–7999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 DOWNERSGRV IL
2014-10-23 331-903-8XXX 8000–8999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 DOWNERSGRV IL
2014-10-22 331-318-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 LEMONT IL
2014-10-14 331-307-8XXX 8000–8999Assigned T-MOBILE USA, INC. 6529 LOMBARD IL
2014-10-14 331-307-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 LOMBARD IL
2014-10-14 331-980-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2014-10-14 331-980-8XXX 8000–8999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2014-10-14 331-980-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2014-10-10 331-228-8XXX 8000–8999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 ST CHARLES IL
2014-10-10 331-702-0XXX 0000–0999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 NAPERVILLE IL
2014-10-10 331-702-1XXX 1000–1999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 NAPERVILLE IL
2014-10-08 331-302-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2014-10-08 331-551-3XXX 3000–3999Assigned T-MOBILE USA, INC. 6529 LOMBARD IL
2014-10-08 331-551-4XXX 4000–4999Assigned T-MOBILE USA, INC. 6529 LOMBARD IL
2014-09-25 331-254-6XXX 6000–6999Assigned T-MOBILE USA, INC. 6529 SUGARGROVE IL
2014-09-25 331-254-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 SUGARGROVE IL
2014-09-25 331-903-6XXX 6000–6999Assigned COMCAST IP PHONE, LLC 318J DOWNERSGRV IL
2014-09-16 331-702-7XXX 7000–7999Assigned TELEPORT COMMUNICATIONS AMERICA, LLC - IL 7136 NAPERVILLE 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.