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
2017-03-28 331-304-2XXX 2000–2999Assigned T-MOBILE USA, INC. 6529 BARTLETT IL
2017-03-28 331-304-3XXX 3000–3999Assigned T-MOBILE USA, INC. 6529 BARTLETT IL
2017-03-28 331-304-4XXX 4000–4999Assigned T-MOBILE USA, INC. 6529 BARTLETT IL
2017-03-28 331-304-5XXX 5000–5999Assigned T-MOBILE USA, INC. 6529 BARTLETT IL
2017-03-28 331-321-0XXX 0000–0999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2017-03-21 331-226-3XXX 3000–3999Assigned T-MOBILE USA, INC. 6529 NAPERVILLE IL
2017-03-21 331-226-4XXX 4000–4999Assigned T-MOBILE USA, INC. 6529 NAPERVILLE IL
2017-03-21 331-226-5XXX 5000–5999Assigned T-MOBILE USA, INC. 6529 NAPERVILLE IL
2017-03-21 331-226-6XXX 6000–6999Assigned T-MOBILE USA, INC. 6529 NAPERVILLE IL
2017-03-21 331-226-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 NAPERVILLE IL
2017-03-21 331-226-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 NAPERVILLE IL
2017-03-17 331-219-0XXX 0000–0999Assigned TELNYX LLC 073H AURORA IL
2017-03-15 331-401-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 NAPERVILLE IL
2017-03-14 331-233-0XXX 0000–0999Assigned TELNYX LLC 073H DOWNERSGRV IL
2017-03-07 331-204-7XXX 7000–7999Assigned TELNYX LLC 073H NAPERVILLE IL
2017-03-07 331-707-2XXX 2000–2999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 AURORA IL
2017-02-22 331-385-7XXX 7000–7999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 AURORA IL
2017-02-22 331-385-8XXX 8000–8999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 AURORA IL
2017-02-01 331-775-1XXX 1000–1999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 DOWNERSGRV IL
2017-02-01 331-775-6XXX 6000–6999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 DOWNERSGRV IL
2017-01-18 331-385-6XXX 6000–6999Assigned ONVOY, LLC 224C AURORA IL
2017-01-16 331-401-6XXX 6000–6999Assigned ONVOY, LLC 224C NAPERVILLE IL
2016-12-30 331-871-5XXX 5000–5999Assigned COMCAST IP PHONE, LLC 318J W CHICAGO IL
2016-12-27 331-315-5XXX 5000–5999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 LOMBARD IL
2016-12-27 331-401-2XXX 2000–2999Assigned CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL 6333 NAPERVILLE IL
2016-12-19 331-717-6XXX 6000–6999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 OSWEGO IL
2016-12-15 331-385-5XXX 5000–5999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 AURORA IL
2016-12-07 331-385-0XXX 0000–0999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2016-12-07 331-385-1XXX 1000–1999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2016-12-07 331-385-2XXX 2000–2999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2016-12-07 331-385-3XXX 3000–3999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2016-12-07 331-385-4XXX 4000–4999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2016-12-07 331-707-3XXX 3000–3999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2016-11-25 331-315-6XXX 6000–6999Assigned T-MOBILE USA, INC. 6529 LOMBARD IL
2016-11-25 331-315-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 LOMBARD IL
2016-11-25 331-315-8XXX 8000–8999Assigned T-MOBILE USA, INC. 6529 LOMBARD IL
2016-11-23 331-871-2XXX 2000–2999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 W CHICAGO IL
2016-11-23 331-871-3XXX 3000–3999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 W CHICAGO IL
2016-11-15 331-707-4XXX 4000–4999Assigned PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E AURORA IL
2016-11-15 331-775-7XXX 7000–7999Assigned PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E DOWNERSGRV IL
2016-11-07 331-775-4XXX 4000–4999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 DOWNERSGRV IL
2016-10-26 331-808-9XXX 9000–9999Assigned PEERLESS NETWORK OF ILLINOIS, LLC - IL 063E PLANO IL
2016-10-20 331-315-2XXX 2000–2999Assigned LEVEL 3 TELECOM OF ILLINOIS, LLC - IL 138G LOMBARD IL
2016-10-12 331-757-7XXX 7000–7999Assigned AT&T ENTERPRISES, LLC 516C LEMONT IL
2016-09-28 331-385-9XXX 9000–9999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 AURORA IL
2016-09-26 331-204-6XXX 6000–6999Assigned COMCAST IP PHONE, LLC 318J NAPERVILLE IL
2016-09-20 331-775-3XXX 3000–3999Assigned ACCESS ONE, INC. - IL 5447 DOWNERSGRV IL
2016-09-01 331-401-8XXX 8000–8999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 NAPERVILLE IL
2016-09-01 331-401-9XXX 9000–9999Assigned NEW CINGULAR WIRELESS PCS, LLC - IL 6534 NAPERVILLE IL
2016-08-24 331-707-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 AURORA 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.