NumberResearch Membership · Data 09/26/2026

Recent thousands-block assignments

0 blocks assigned in the last 30 days · from the daily NANPA thousands-block report, 09/26/2026

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 857
MCIMETRO ACCESS TRANSMISSION SERVICES LLC 76
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
2023-02-27 857-416-3XXX 3000–3999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2022-07-20 857-767-4XXX 4000–4999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2021-12-08 857-394-3XXX 3000–3999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BELMONT MA
2020-01-06 857-353-2XXX 2000–2999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2020-01-06 857-353-3XXX 3000–3999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2020-01-06 857-353-4XXX 4000–4999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2019-12-23 857-703-4XXX 4000–4999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 HYDE PARK MA
2019-12-06 857-557-2XXX 2000–2999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2018-02-01 857-338-2XXX 2000–2999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2018-02-01 857-338-3XXX 3000–3999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2017-06-12 857-409-3XXX 3000–3999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2017-05-23 857-443-2XXX 2000–2999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2017-03-10 857-378-2XXX 2000–2999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2016-12-06 857-409-2XXX 2000–2999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2016-06-27 857-385-3XXX 3000–3999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 DORCHESTER MA
2016-05-18 857-352-5XXX 5000–5999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BROOKLINE MA
2016-02-26 857-504-7XXX 7000–7999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2015-10-29 857-316-3XXX 3000–3999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BRIGHTON MA
2015-10-29 857-504-3XXX 3000–3999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2015-06-26 857-957-3XXX 3000–3999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2015-01-02 857-317-5XXX 5000–5999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2014-05-08 857-415-5XXX 5000–5999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2014-01-30 857-313-7XXX 7000–7999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2014-01-03 857-415-4XXX 4000–4999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2013-11-12 857-415-3XXX 3000–3999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2013-11-07 857-626-3XXX 3000–3999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BELMONT MA
2012-04-30 857-293-5XXX 5000–5999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 EASTBOSTON MA
2011-12-01 857-202-3XXX 3000–3999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2011-12-01 857-202-4XXX 4000–4999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2011-12-01 857-202-5XXX 5000–5999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2011-12-01 857-202-6XXX 6000–6999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2011-11-04 857-500-4XXX 4000–4999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 CAMBRIDGE MA
2011-11-02 857-400-2XXX 2000–2999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2011-09-16 857-300-2XXX 2000–2999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2011-08-12 857-263-4XXX 4000–4999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2011-08-12 857-263-5XXX 5000–5999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2011-08-12 857-263-6XXX 6000–6999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2011-05-27 857-321-5XXX 5000–5999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2011-05-27 857-321-6XXX 6000–6999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2011-05-10 857-600-3XXX 3000–3999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 CAMBRIDGE MA
2011-05-10 857-600-4XXX 4000–4999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 CAMBRIDGE MA
2011-04-12 857-400-3XXX 3000–3999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2010-01-29 857-246-7XXX 7000–7999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2009-09-28 857-288-2XXX 2000–2999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2009-09-28 857-288-3XXX 3000–3999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2009-09-28 857-288-4XXX 4000–4999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2009-04-15 857-244-6XXX 6000–6999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2008-04-23 857-284-0XXX 0000–0999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2008-04-23 857-284-1XXX 1000–1999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA
2007-11-09 857-350-8XXX 8000–8999Assigned MCIMETRO ACCESS TRANSMISSION SERVICES LLC 7229 BOSTON MA

Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/26/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.