NumberResearchRecent thousands-block assignments
0 blocks assigned in the last 30 days · from the daily NANPA thousands-block report, 09/19/2026
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 731
New assignments by month
Sep 2026
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2017-02-15 | 731-319-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | TIPTONVL | TN |
| 2016-12-01 | 731-574-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | JACKSON | TN |
| 2016-10-21 | 731-220-4XXX | 4000–4999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CAMDEN | TN |
| 2016-10-21 | 731-221-4XXX | 4000–4999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | RIPLEY | TN |
| 2016-10-21 | 731-318-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | MILAN | TN |
| 2016-10-05 | 731-330-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | TRENTON | TN |
| 2016-10-05 | 731-982-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | SELMER | TN |
| 2016-09-13 | 731-741-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | BROWNSVL | TN |
| 2014-11-24 | 731-410-4XXX | 4000–4999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | JACKSON | TN |
| 2012-01-04 | 731-412-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | SAVANNAH | TN |
| 2012-01-04 | 731-418-6XXX | 6000–6999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | HUNTINGDON | TN |
| 2010-12-29 | 731-337-6XXX | 6000–6999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | HUMBOLDT | TN |
| 2010-10-20 | 731-540-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | PARIS | TN |
| 2010-05-25 | 731-307-4XXX | 4000–4999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | LEXINGTON | TN |
| 2010-04-15 | 731-599-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | UNION CITY | TN |
| 2006-03-13 | 731-518-4XXX | 4000–4999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | BOLIVAR | TN |
| 2006-03-13 | 731-882-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | DYERSBURG | TN |
| 2005-09-19 | 731-256-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | JACKSON | TN |
| 2005-04-20 | 731-472-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | MIDDLETON | TN |
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.