APM is jointly owned by, and provides services to, the following 17 power supply cooperatives (APM also provides services to numerous Clients):
Arizona Electric Power Cooperative
Brazos Electric Power Cooperative
Big Rivers Electric Corporation
Buckeye Power
Central Iowa Power Cooperative
East Kentucky Power Cooperative
Golden Spread Electric Cooperative
Great River Energy
Hoosier Energy
North Carolina Electric Membership Corporation
Old Dominion Electric Cooperative
Oglethorpe Power Corporation
Southern Illinois Power Cooperative
Southern Maryland Electric Cooperative
Sunflower Electric Power Corporation
Western Farmers Electric Cooperative
Wabash Valley Power Association