The Southern Company (Southern Company) owns all of the outstanding common stock of Alabama Power, Georgia Power, Gulf Power, and Mississippi Power, each of which is an operating public utility company. The traditional operating companies supply electric service in the states of Alabama, Georgia, Florida, and Mississippi. In addition, Southern Company owns all of the common stock of Southern Power, which is also an operating public utility company. Southern Power constructs, acquires, owns, and manages generation assets and sells electricity at market-based rates in the wholesale market. Southern Company also owns all the outstanding common stock or membership interests of SouthernLINC Wireless, Southern Nuclear, Southern Company Services, Inc., Southern Holdings and other direct and indirect subsidiaries. In June 2008, Southern Power completed construction on Plant Franklin Unit 3, which added 659 megawatts to the Southern Company system generating capacity.