Alcoa
Ameren Corporation
- Ameren Illinois
- Ameren Missouri
- Ameren Transmission
American Electric Power System
- Appalachian Power Company
- AEP Generating Company
- AEP Generation Resources Inc.
- Columbus Southern Power Company
- Indiana Michigan Power Company
- Kentucky Power Company
- Ohio Power Company
- Public Service Company of Oklahoma
- Southwestern Electric Power Company
- Wheeling Power Company