The Southern Company, through its subsidiaries, engages in the generation, transmission, and distribution of electricity. The company also develops, constructs, acquires, owns, and manages power generation assets, including renewable energy projects and sells electricity in the wholesale market; and distributes natural gas in Illinois, Georgia, Virginia, and Tennessee, as well as provides gas marketing services, gas distribution operations, and gas pipeline investments operations. In addition, it owns and operates nuclear, coal, hydro, cogeneration, solar, wind, battery storage, and fuel cell facilities. Further, the constructs, operates, and maintains approximately 77,900 miles of natural gas pipelines and 14 storage facilities with total capacity of 157 Bcf to provide natural gas to residential, commercial, and industrial customers. The company serves approximately 8.9 million electric and gas utility customers. Further, it develops distributed energy and resilience solutions; deploys microgrids for commercial, industrial, governmental, and utility customers; and offers digital wireless communications and fiber optics services. The Southern Company was incorporated in 1945 and is headquartered in Atlanta, Georgia.

Atmos Energy Corporation, together with its subsidiaries, engages in the regulated natural gas distribution, and pipeline and storage businesses in the United States. It operates through two segments, Distribution, and Pipeline and Storage. The Distribution segment is involved in the regulated natural gas distribution and related sales operations in eight states. This segment distributes natural gas to approximately 3.3 million residential, commercial, public authority, and industrial customers; and owned 73,689 miles of underground distribution and transmission mains. The Pipeline and Storage segment engages in the pipeline and storage operations. This segment transports natural gas for third parties and manages five underground storage facilities in Texas; provides ancillary services customary to the pipeline industry, including parking arrangements, lending, and inventory sales; and owned 5,645 miles of gas transmission lines. Atmos Energy Corporation was founded in 1906 and is headquartered in Dallas, Texas.

Pinnacle West Capital Corporation, through its subsidiary, provides retail and wholesale electric services primarily in the state of Arizona. The company engages in the generation, transmission, and distribution of electricity using coal, nuclear, gas, oil, and solar generating facilities. Its transmission facilities include overhead lines and underground lines; and distribution facilities consist of overhead lines and underground primary cables. The company also owns and maintains transmission and distribution substations; and owns energy storage facilities. Pinnacle West Capital Corporation was incorporated in 1985 and is headquartered in Phoenix, Arizona.

Southwestern Energy Company, an independent energy company, engages in the exploration, development, and production of natural gas, oil, and natural gas liquids (NGLs) in the United States. It operates through two segments, Exploration and Production, and Marketing. The company focuses on the development of unconventional natural gas and oil reservoirs located in Pennsylvania, West Virginia, Ohio, and Louisiana. It also engages in the marketing and transportation of natural gas, oil, and NGLs. It serves LNG exporters, energy companies, utilities, and industrial purchasers of natural gas. Southwestern Energy Company was incorporated in 1929 and is headquartered in Spring, Texas.

ONE Gas, Inc., together with its subsidiaries, operates as a regulated natural gas distribution company in the United States. The company provides natural gas distribution services to approximately 2.3 million customers in Oklahoma, Kansas, and Texas. It serves residential, commercial, and transportation customers. The company was founded in 1906 and is headquartered in Tulsa, Oklahoma.

Black Hills Corporation, through its subsidiaries, operates as an electric and natural gas utility company in the United States. The company operates in two segments: Electric Utilities and Gas Utilities. The Electric Utilities segment generates, transmits, and distributes electricity to approximately 222,000 electric utility customers in Colorado, Montana, South Dakota, and Wyoming; and owns and operates 1,394 megawatts of generation capacity and 9,106 miles of electric transmission and distribution lines. The Gas Utilities segment distributes natural gas to approximately 1,116,000 natural gas utility customers in Arkansas, Colorado, Iowa, Kansas, Nebraska, and Wyoming; owns and operates 4,663 miles of intrastate gas transmission pipelines; 42,514 miles of gas distribution mains and service lines; seven natural gas storage sites; and approximately 50,000 horsepower of compression and 516 miles of gathering lines. It also constructs and maintains customer owned gas infrastructure facilities for gas transportation customers; and provides appliance repair services to residential utility customers, as well as electrical system construction services to large industrial customers. In addition, the company produces electric power through wind, natural gas, and coal-fired generating plants; and coal at its coal mine located near Gillette, Wyoming. Black Hills Corporation was incorporated in 1941 and is headquartered in Rapid City, South Dakota.

Northwest Natural Holding Company, through its subsidiary, Northwest Natural Gas Company, provides regulated natural gas distribution services to residential, commercial, and industrial customers in the United States. The company operates a mist gas storage facility contracted to other utilities, third-party marketers, and electric generators; offers natural gas asset management services; and operates an appliance retail center. It also engages in gas storage, water and wastewater, non-regulated renewable natural gas, and other investment businesses. In addition, the company provides natural gas service in Oregon and southwest Washington; and water and wastewater connections. Northwest Natural Holding Company was founded in 1859 and is headquartered in Portland, Oregon.

Centuri Holdings, Inc. operates as a utility infrastructure services company in North America. It offers gas utility services, including maintenance, repair, installation, and replacement services for natural gas local distribution utility companies with focus on the modernization of infrastructure. The company also provides electric utility services comprising design, maintenance and repair, upgrade, and expansion services for transmission and distribution infrastructure. Its customers include electric, gas, and combination utility companies, as well as serves end markets, such as renewable energy and 5G datacom. The company was founded in 1909 and is headquartered in Phoenix, Arizona. Centuri Holdings, Inc. is a subsidiary of Southwest Gas Holdings, Inc.