Pinnacle West is a holding company whose business is essentially entirely its regulated electric utility subsidiary, Arizona Public Service (APS). APS is Arizona's largest electric utility, serving approximately 1.4 million customers across most of Arizona, centered on the Phoenix metro area. APS generates, transmits, and distributes electricity to residential, commercial, and industrial customers at regulated retail rates set by the Arizona Corporation Commission (ACC). APS owns 6,257 MW of generation capacity, with a mix of nuclear (anchored by the Palo Verde Generating Station), natural gas, coal, and solar and battery storage, supplemented by third-party PPAs. Roughly 58% of APS's energy supply comes from clean sources. APS earns a regulated return on its rate base, so earnings grow as APS invests capital into generation and grid infrastructure and recovers those investments through rates. APS is in the middle of a large capital expansion program driven by rapid load growth in Arizona, including nearly 35,000 new residential meters added in 2025 and roughly 4.5 GW of committed demand from large C&I customers, primarily data centers and semiconductor manufacturers like TSMC and Amkor. APS is developing up to 2,000 MW of new gas generation near Gila Bend and is expanding its high-voltage transmission network. APS is guiding to 7%-9% rate base growth through 2028, and is pursuing a formula rate plan to reduce regulatory lag in cost recovery.