NumberResearchRecent thousands-block assignments
0 blocks assigned in the last 30 days · from the daily NANPA thousands-block report, 09/25/2026
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 312
New assignments by month
Sep 2026
Aug 2026
Jul 2026
Jun 2026
May 2026
Apr 2026
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Dec 2025
Nov 2025
Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2019-08-15 | 312-668-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2018-08-07 | 312-736-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2018-08-07 | 312-736-4XXX | 4000–4999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2017-05-01 | 312-319-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2017-02-17 | 312-270-2XXX | 2000–2999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2016-06-21 | 312-824-2XXX | 2000–2999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2016-06-21 | 312-824-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2016-06-21 | 312-824-4XXX | 4000–4999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2015-06-30 | 312-471-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2015-06-30 | 312-471-4XXX | 4000–4999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2015-06-30 | 312-471-5XXX | 5000–5999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2015-03-24 | 312-897-2XXX | 2000–2999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2015-03-24 | 312-897-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2015-03-24 | 312-897-4XXX | 4000–4999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2015-02-10 | 312-517-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2015-02-10 | 312-517-4XXX | 4000–4999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2014-11-25 | 312-792-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2014-06-13 | 312-763-4XXX | 4000–4999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2014-06-13 | 312-763-5XXX | 5000–5999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2014-02-25 | 312-973-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2014-02-25 | 312-973-4XXX | 4000–4999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2013-10-29 | 312-809-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2013-10-29 | 312-809-4XXX | 4000–4999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2013-07-31 | 312-801-7XXX | 7000–7999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2013-04-19 | 312-585-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2013-04-19 | 312-585-4XXX | 4000–4999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2013-01-25 | 312-702-4XXX | 4000–4999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2013-01-03 | 312-702-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2012-10-01 | 312-619-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2012-09-11 | 312-610-8XXX | 8000–8999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - IL | 7196 | CHICGOZN01 | IL |
| 2012-08-29 | 312-610-4XXX | 4000–4999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2012-08-29 | 312-610-5XXX | 5000–5999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2012-08-29 | 312-610-6XXX | 6000–6999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2012-08-29 | 312-610-7XXX | 7000–7999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2012-04-04 | 312-448-2XXX | 2000–2999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2011-05-17 | 312-929-0XXX | 0000–0999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2010-12-22 | 312-528-7XXX | 7000–7999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2010-12-22 | 312-554-6XXX | 6000–6999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2010-12-22 | 312-582-4XXX | 4000–4999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2010-12-22 | 312-589-7XXX | 7000–7999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2010-12-22 | 312-674-7XXX | 7000–7999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2010-12-22 | 312-983-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2010-11-18 | 312-999-4XXX | 4000–4999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2010-11-18 | 312-999-5XXX | 5000–5999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2010-11-18 | 312-999-6XXX | 6000–6999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2010-11-04 | 312-999-1XXX | 1000–1999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2010-10-15 | 312-361-9XXX | 9000–9999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2010-10-15 | 312-526-6XXX | 6000–6999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2010-01-15 | 312-428-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
| 2010-01-15 | 312-488-5XXX | 5000–5999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CHICGOZN01 | IL |
Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/25/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.