NumberResearchRecent thousands-block assignments
0 blocks assigned in the last 30 days · from the daily NANPA thousands-block report, 09/26/2026
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 313
New assignments by month
Sep 2026
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2017-06-12 | 313-426-5XXX | 5000–5999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2017-06-12 | 313-426-6XXX | 6000–6999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2013-10-24 | 313-545-0XXX | 0000–0999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2013-10-24 | 313-545-1XXX | 1000–1999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2013-10-24 | 313-545-2XXX | 2000–2999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2013-10-24 | 313-545-3XXX | 3000–3999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2013-10-24 | 313-545-4XXX | 4000–4999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2013-10-24 | 313-545-5XXX | 5000–5999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2013-10-24 | 313-545-6XXX | 6000–6999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2013-10-24 | 313-545-7XXX | 7000–7999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2013-10-24 | 313-545-8XXX | 8000–8999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2013-10-24 | 313-545-9XXX | 9000–9999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2012-06-26 | 313-782-0XXX | 0000–0999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2012-06-26 | 313-782-7XXX | 7000–7999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2012-06-26 | 313-782-8XXX | 8000–8999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2012-06-26 | 313-782-9XXX | 9000–9999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2011-10-11 | 313-338-0XXX | 0000–0999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2011-10-11 | 313-338-1XXX | 1000–1999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2011-10-11 | 313-338-2XXX | 2000–2999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2010-12-09 | 313-448-0XXX | 0000–0999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2010-12-09 | 313-448-1XXX | 1000–1999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2010-12-09 | 313-448-2XXX | 2000–2999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2010-12-09 | 313-448-3XXX | 3000–3999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2010-12-09 | 313-448-4XXX | 4000–4999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2010-12-09 | 313-448-5XXX | 5000–5999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2010-12-09 | 313-448-6XXX | 6000–6999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2010-12-09 | 313-448-7XXX | 7000–7999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2010-12-09 | 313-448-8XXX | 8000–8999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2009-10-07 | 313-373-0XXX | 0000–0999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2009-10-07 | 313-373-1XXX | 1000–1999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2009-10-07 | 313-373-2XXX | 2000–2999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2009-10-07 | 313-373-3XXX | 3000–3999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2009-10-07 | 313-373-4XXX | 4000–4999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2009-10-07 | 313-373-5XXX | 5000–5999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2009-10-07 | 313-373-6XXX | 6000–6999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2009-10-07 | 313-373-7XXX | 7000–7999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2009-10-07 | 313-373-8XXX | 8000–8999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2009-10-07 | 313-373-9XXX | 9000–9999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2008-10-09 | 313-482-2XXX | 2000–2999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2008-10-09 | 313-482-3XXX | 3000–3999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2008-10-09 | 313-482-4XXX | 4000–4999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
| 2008-08-07 | 313-473-1XXX | 1000–1999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN2 | MI |
| 2008-08-07 | 313-473-2XXX | 2000–2999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN2 | MI |
| 2008-08-07 | 313-473-3XXX | 3000–3999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN2 | MI |
| 2008-08-07 | 313-473-4XXX | 4000–4999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN2 | MI |
| 2008-08-07 | 313-473-5XXX | 5000–5999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN2 | MI |
| 2008-08-07 | 313-473-6XXX | 6000–6999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN2 | MI |
| 2005-06-20 | 313-221-2XXX | 2000–2999 | Assigned | MICHIGAN BELL TEL CO | 9323 | DETROITZN1 | MI |
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.