PINNACLE WEST CAPITAL CORP

Pinnacle West Pinnacle West is an investor-owned electric utility holding company based in Phoenix, Arizona with consolidated assets of approximately $30 billion. We derive essentially all of our revenues and earnings from our principal subsidiary, APS. Since 1886, APS and its affiliates have provided energy and energy-related products to people and businesses throughout Arizona. APS is Arizona’s largest and longest-serving electric company and generates safe, affordable electricity in 11 of Arizona’s 15 counties. Our other active subsidiaries are El Dorado and PNW Power. Our reportable business segment is our regulated electricity segment, which consists of traditional regulated retail and wholesale electricity businesses (primarily electric service to Native Load customers) and related activities, and includes electricity generation, transmission, and distribution. Our reportable business segment activities are conducted primarily through our wholly-owned subsidiary, APS. 3 Table of Contents BUSINESS OF ARIZONA PUBLIC SERVICE COMPANY APS currently provides electric service to approximately 1.4 million customers. We own or lease 6,257 MW of regulated generation capacity, and we hold a mix of both long-term and short-term PPAs for additional capacity. During 2025, no single purchaser or user of energy accounted for more than 1.9% of our electric revenues. The following map shows APS’s retail service territory, including the locations of its generating facilities and principal transmission lines.