Pinnacle West

Arizona Public Service Company is the largest electric utility in Arizona, United States, and the principal subsidiary of publicly traded S&P 500 member Pinnacle West Capital Corporation (NYSE: PNW), which in turn had been formerly named AZP Group, when Arizona Public Service reorganized as that holding company in 1985. With 4,000 MW of generating capacity, APS serves more than one million customers in 11 counties throughout most of the state, but mainly concentrated in northern and central Arizona. APS is one of the two major suppliers of electricity to the Phoenix metropolitan area (the other being Salt River Project).APS is regulated by the Arizona Corporation Commission (ACC), the state agency that, by mandate of Article 15, Section 2 of the state's constitution, regulates energy utilities in Arizona, with the notable exception of SRP, the rural electrical districts, and the City of Mesa electric utility serving Downtown Mesa and the immediate vicinity (with the rest of the city being served by SRP).