Ameritech Michigan COLD
d/b/a AT&T Michigan
Holding: AT&T Inc
2000 W Att Center Dr, Room 4G33A
Hoffman Estates, IL 60192-5005
AT&T Michigan
2001-01-15
2019-10-31
Several years old. Contact the number directly.
Ameritech Michigan issued these blocks several years ago. Customers swap carriers every few years, so Ameritech Michigan probably no longer holds them. Try calling any number you're interested in. If a person answers, you've found the current owner and can negotiate with them.
A long shot: if you'd like a watch in case we ever gain access to Ameritech Michigan's inventory directly, you can register your interest. We don't currently have visibility into number changes within carriers, so don't count on it.
About AT&T Michigan
AT&T Michigan (The Michigan Bell Telephone Company) is a Regional Bell Operating Company (RBOC) subsidiary of AT&T Inc. that provides wireline, fiber, wireless, and fixed wireless internet services across Michigan. The carrier serves both consumer and business customers through retail and wholesale channels, operating as part of AT&T's broader national network covering over 99% of Americans.
- Parent: AT&T Inc.
- Headquarters: Hoffman Estates, IL
- Services: wireline local exchange, fiber broadband (AT&T Fiber), fixed wireless internet (AT&T Internet Air), wireless voice and data, wholesale/interexchange
Sources: AT&T Michigan Guidebook Part 1 · Michigan Public Service Commission - Interexchange and Competitive Access Providers List (April 24, 2026) · How AT&T is Investing in Michigan
Toll-free side: Related toll-free RespOrg: AT&T (code BSSB1). View on resporgs.com →
Carrier website
att.com: opens in a new tab
HQ: Hoffman Estates, IL
Block portfolio at a glance
By age
- Recent (0). Last 18 mo
- Medium (0)
- Old (312)
- Undated (4,723)
Footprint by state
Stronger blue = more blocks issued in that state. ● marks states with activity in the last 18 months.
- Michigan MI · 5,035
Top area codes
Bars show total blocks; red overlay is recent.
Block assignments by year
Sister OCNs under AT&T Inc
| OCN | Company | Total | Recent |
|---|---|---|---|
| 6534 | New Cingular Wireless PCS LLC - IL | 58,704 | 6,826 |
| 6214 | New Cingular Wireless PCS LLC - GA | 40,046 | 5,473 |
| 6010 | New Cingular Wireless PCS LLC | 38,106 | 3,019 |
| 4036 | New Cingular Wireless PCS LLC - DC | 30,944 | 4,342 |
| 9533 | Southwestern Bell Telephone Company | 26,095 | 0 |
| 9740 | Pacific Bell Telephone Company | 18,541 | 0 |
| 9417 | Bellsouth Telecommunications Inc dba Southern Bell Telephone & Telegraph | 15,734 | 0 |
| 9419 | Bellsouth Telecommunications Inc dba South Central Bell Telephone | 13,075 | 0 |
| 9329 | Ameritech Illinois | 6,645 | 0 |
| 516C | AT&T Enterprises LLC | 5,935 | 113 |
| 9321 | Ameritech Ohio | 4,377 | 0 |
| 9325 | Ameritech Indiana | 2,941 | 0 |