Top Utilities Companies in USA List by Market Cap as of August 2026

American States Water Company is the Parent of Golden State Water Company. The company serving over one million people in nine states provides water service to approximately 2,61,000 customer connections located within more than 80 communities and distributes electricity to approximately 24,000 customer connections in the City of Big Bear Lake and surrounding areas in San Bernardino County, California. The headquarters is in USA.

Avista Corporation is a Energy company. It involved in the production, transmission and distribution of energy as well as other energy related businesses. The company operating division, providing electricity to nearly 3,40,000 customers and natural gas to about 3,00,000 customers across 30,000 square miles and four northwestern states. The headquarters is in USA.

California Water Service Group is a Third Largest Publicly Traded Water Utility in the United States. It is providing high quality water and wastewater services to more than two million people in over 100 communities. The headquarters is in USA.

Electric utility and natural gas distribution company. Headquarters is in USA. Produces electricity as well.

Holly Energy Partners is a Oil company. It provides petroleum product and crude oil transportation, terminalling services, storage and through out services to the petroleum industry including HollyFrontier Corporation subsidiaries. The headquarters is in USA.

HF Sinclair Corporation acquired Holly Energy Partners in 2023. Post that Holly Energy Partners was delisted.

HF Sinclair Corporation is a listed company on stock exchanges.

TC PipeLines LP is a Natural Gas Infrastructure company. It demand continues to increase as electrical generation, industrial sectors and residential users seek increased use of cleaner burning natural gas for their power, heating and cooling needs. The company is having more than 7,300 TC Energy employees make a positive difference in the communities where the company operates across Canada, the U.S. and Mexico. The headquarters is in USA.