NumberResearch Membership · Data 09/19/2026

Recent thousands-block assignments

0 blocks assigned in the last 30 days · from the daily NANPA thousands-block report, 09/19/2026

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 331
T-MOBILE USA, INC. 281
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
2025-08-12 331-327-3XXX 3000–3999Assigned T-MOBILE USA, INC. 6529 ST CHARLES IL
2024-11-13 331-341-4XXX 4000–4999Assigned T-MOBILE USA, INC. 6529 PLANO IL
2024-10-22 331-314-1XXX 1000–1999Assigned T-MOBILE USA, INC. 6529 ST CHARLES IL
2024-02-26 331-225-8XXX 8000–8999Assigned T-MOBILE USA, INC. 6529 ELMHURST IL
2024-02-08 331-314-2XXX 2000–2999Assigned T-MOBILE USA, INC. 6529 ST CHARLES IL
2024-02-08 331-314-3XXX 3000–3999Assigned T-MOBILE USA, INC. 6529 ST CHARLES IL
2024-02-08 331-314-4XXX 4000–4999Assigned T-MOBILE USA, INC. 6529 ST CHARLES IL
2024-02-07 331-341-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 PLANO IL
2024-02-07 331-341-8XXX 8000–8999Assigned T-MOBILE USA, INC. 6529 PLANO IL
2024-02-07 331-341-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 PLANO IL
2024-01-09 331-224-1XXX 1000–1999Assigned T-MOBILE USA, INC. 6529 ITASCA IL
2024-01-09 331-224-8XXX 8000–8999Assigned T-MOBILE USA, INC. 6529 ITASCA IL
2023-09-26 331-217-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 LOMBARD IL
2022-08-30 331-600-2XXX 2000–2999Assigned T-MOBILE USA, INC. 6529 WHEATON IL
2022-08-30 331-600-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 WHEATON IL
2022-08-15 331-289-6XXX 6000–6999Assigned T-MOBILE USA, INC. 6529 HINSDALE IL
2022-08-15 331-289-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 HINSDALE IL
2022-08-11 331-299-0XXX 0000–0999Assigned T-MOBILE USA, INC. 6529 HINSDALE IL
2022-04-26 331-600-4XXX 4000–4999Assigned T-MOBILE USA, INC. 6529 WHEATON IL
2022-04-26 331-600-5XXX 5000–5999Assigned T-MOBILE USA, INC. 6529 WHEATON IL
2022-03-22 331-277-5XXX 5000–5999Assigned T-MOBILE USA, INC. 6529 LOMBARD IL
2022-03-22 331-627-0XXX 0000–0999Assigned T-MOBILE USA, INC. 6529 LOMBARD IL
2022-03-22 331-627-1XXX 1000–1999Assigned T-MOBILE USA, INC. 6529 LOMBARD IL
2022-03-11 331-284-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 BARTLETT IL
2022-02-23 331-283-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 GENEVA IL
2022-01-08 331-282-5XXX 5000–5999Assigned T-MOBILE USA, INC. 6529 HINSDALE IL
2022-01-08 331-282-6XXX 6000–6999Assigned T-MOBILE USA, INC. 6529 HINSDALE IL
2021-08-03 331-274-2XXX 2000–2999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2021-08-03 331-274-3XXX 3000–3999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2021-08-03 331-274-4XXX 4000–4999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2021-08-03 331-274-5XXX 5000–5999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2021-08-03 331-274-6XXX 6000–6999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2021-08-03 331-274-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2021-08-03 331-274-8XXX 8000–8999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2021-08-03 331-274-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2021-08-03 331-275-6XXX 6000–6999Assigned T-MOBILE USA, INC. 6529 BARTLETT IL
2021-08-03 331-275-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 BARTLETT IL
2021-08-03 331-275-8XXX 8000–8999Assigned T-MOBILE USA, INC. 6529 BARTLETT IL
2021-08-03 331-275-9XXX 9000–9999Assigned T-MOBILE USA, INC. 6529 BARTLETT IL
2021-08-02 331-270-5XXX 5000–5999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2021-08-02 331-270-6XXX 6000–6999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2021-08-02 331-270-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 AURORA IL
2021-06-25 331-304-7XXX 7000–7999Assigned T-MOBILE USA, INC. 6529 BARTLETT IL
2021-06-25 331-356-2XXX 2000–2999Assigned T-MOBILE USA, INC. 6529 BARTLETT IL
2021-06-25 331-356-3XXX 3000–3999Assigned T-MOBILE USA, INC. 6529 BARTLETT IL
2021-06-25 331-356-4XXX 4000–4999Assigned T-MOBILE USA, INC. 6529 BARTLETT IL
2021-06-25 331-356-6XXX 6000–6999Assigned T-MOBILE USA, INC. 6529 BARTLETT IL
2021-06-25 331-788-0XXX 0000–0999Assigned T-MOBILE USA, INC. 6529 GENEVA IL
2021-06-25 331-788-1XXX 1000–1999Assigned T-MOBILE USA, INC. 6529 GENEVA IL
2021-05-14 331-269-4XXX 4000–4999Assigned T-MOBILE USA, INC. 6529 AURORA IL

Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/19/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.