The Williams Companies, Inc., together with its subsidiaries, operates as an energy infrastructure company primarily in the United States. It operates through Transmission & Gulf of Mexico, Northeast G&P, West, and Gas & NGL Marketing Services segments. The Transmission & Gulf of Mexico segment comprises natural gas pipelines; Transco, Northwest pipeline, MountainWest, and related natural gas storage facilities; and natural gas gathering and processing, and crude oil production handling and transportation assets in the Gulf Coast region. The Northeast G&P segment engages in the midstream gathering, processing, and fractionation activities in the Marcellus Shale region primarily in Pennsylvania and New York, and the Utica Shale region of eastern Ohio. The West segment consists of gas gathering, processing, and treating operations in the Rocky Mountain region of Colorado and Wyoming, the Barnett Shale region of north-central Texas, the Eagle Ford Shale region of South Texas, the Haynesville Shale region of northwest Louisiana, the Mid-Continent region that includes the Anadarko and Permian basins, and the DJ Basin of Colorado; and operates natural gas liquid (NGL) fractionation and storage facilities in central Kansas near Conway. The Gas & NGL Marketing Services segment provides wholesale marketing, trading, storage, and transportation of natural gas for natural gas utilities, municipalities, power generators, and producers; asset management services; and transports and markets NGLs. The company owns and operates 33,000 miles of pipelines. The Williams Companies, Inc. was founded in 1908 and is headquartered in Tulsa, Oklahoma.

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.

NiSource Inc., an energy holding company, operates as a regulated natural gas and electric utility company in the United States. It operates in two segments, Gas Distribution Operations and Electric Operations. The company distributes natural gas to approximately 3.3 million customers through approximately 55,000 miles of distribution main pipeline and the associated individual customer service lines; and 1,000 miles of transmission main pipeline in northern Indiana, Ohio, Pennsylvania, Virginia, Kentucky, and Maryland. It also generates, transmits, and distributes electricity to approximately 0.5 million customers in various counties in the northern part of Indiana, as well as engages in wholesale electric and transmission transactions. It owns and operates coal-fired electric generating stations in Wheatfield and Michigan City; combined cycle gas turbine in West Terre Haute; natural gas generating units in Wheatfield; hydro generating plants in Carroll County and White County; wind generating units in White County, Indiana; and solar generating units in Jasper County and White County. The company was formerly known as NIPSCO Industries, Inc. and changed its name to NiSource Inc. in April 1999. NiSource Inc. was founded in 1847 and is headquartered in Merrillville, Indiana.

Southwest Gas Holdings, Inc., through its subsidiaries, distributes and transports natural gas in Arizona, Nevada, and California. The company operates through Natural Gas Distribution, Utility Infrastructure Services, and Pipeline and Storage segments. It also provides trenching, installation, and replacement of underground pipes, as well as maintenance services for energy distribution systems. As of December 31, 2023, it had 2,226,000 residential, commercial, industrial, and other natural gas customers. Southwest Gas Holdings, Inc. was incorporated in 1931 and is headquartered in Las Vegas, Nevada.

New Jersey Resources Corporation, an energy services holding company, distributes natural gas. The company operates through four segments: Natural Gas Distribution, Clean Energy Ventures, Energy Services, and Storage and Transportation. The Natural Gas Distribution segment offers regulated natural gas utility services to approximately 576,000 customers in Burlington, Middlesex, Monmouth, Morris, Ocean, and Sussex counties in New Jersey; provides capacity and storage management services; and participates in the off-system sales and capacity release markets. The Clean Energy Ventures segment invests in, owns, and operates clean energy projects, including commercial and residential solar installation situated in New Jersey, Rhode Island, New York, Connecticut, Michigan, and Indiana. The Energy Services segment maintains and operates natural gas transportation and storage capacity contracts, as well as provides physical wholesale energy, retail energy and energy management services in the United States and Canada. The Storage and Transportation segment invests in invests in energy-related ventures. It provides heating, ventilation, and cooling services; sales and installation of appliances; offers solar equipment installation, and plumbing repair and installation services; and holds commercial real estate properties. The company was incorporated in 1981 and is headquartered in Wall, New Jersey.

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.

NorthWestern Energy Group, Inc. provides electricity and natural gas to residential, commercial, and various industrial customers. It generates, purchases, transmits, and distributes electricity; and produces, purchases, stores, transmits, and distributes natural gas, as well as owns municipal franchises to provide natural gas service in the communities. The company operates 6,600 miles of electric transmission and 18,674 miles of electric distribution lines with approximately 395 transmission and distribution substations; and 2,235 miles of natural gas transmission and 5,155 miles of natural gas distribution lines with approximately 133 city gate stations in Montana. It also operates 1,310 miles of electric transmission and 2,365 miles of electric distribution lines in South Dakota with approximately 124 transmission and distribution substations; and 55 miles of natural gas transmission and 2,573 miles of natural gas distribution lines in South Dakota and Nebraska. The company provides electricity and/or natural gas to approximately 775,300 customers in Montana, South Dakota, Nebraska, and Yellowstone National Park. NorthWestern Energy Group, Inc. was founded in 1923 and is based in Sioux Falls, South Dakota.

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.