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.

National Grid plc transmits and distributes electricity and gas. It operates through UK Electricity Transmission, UK Electricity Distribution, UK Electricity System Operator, New England, New York, National Grid Ventures, and Other segments. The UK Electricity Transmission segment provides electricity transmission and construction work services in England and Wales. The UK Electricity Distribution segment offers electricity distribution services in Midlands, and South West of England and South Wales. The UK Electricity System Operator segment provides balancing services for supply and demand of electricity on Great Britain's electricity transmission system; and acts as an agent on behalf of transmission operators. The New England segment offers electricity and gas distribution, and electricity transmission services in New England. The New York segment provides electricity and gas distribution, and electricity transmission services in New York. The National Grid Ventures segment provides transmission services through electricity interconnectors and LNG importation at the Isle of Grain, as well as sale of renewables projects. The Other segment engages in the leasing and sale of commercial property, as well as insurance activities in the United Kingdom. The company was founded in 1990 and is headquartered in London, the United Kingdom.

ONEOK, Inc. engages in gathering, processing, fractionation, storage, transportation, and marketing of natural gas and natural gas liquids (NGL) in the United States. It operates through four segments: Natural Gas Gathering and Processing, Natural Gas Liquids, Natural Gas Pipelines, and Refined Products and Crude. The company owns natural gas gathering pipelines and processing plants in the Mid-Continent and Rocky Mountain regions; and provides midstream services to producers of NGLs. It also owns NGL gathering and distribution pipelines in Oklahoma, Kansas, Texas, New Mexico, Montana, North Dakota, Wyoming, and Colorado; terminal and storage facilities in Kansas, Nebraska, Iowa, and Illinois; NGL distribution pipelines in Kansas, Nebraska, Iowa, Illinois, and Indiana; transports refined petroleum products, including unleaded gasoline and diesel; and owns and operates truck- and rail-loading, and -unloading facilities connected to NGL fractionation, storage, and pipeline assets. In addition, the company transports and stores natural gas through regulated interstate and intrastate natural gas transmission pipelines, and natural gas storage facilities. Further, it owns and operates a parking garage in downtown Tulsa, Oklahoma; and leases excess office space and rail cars. Additionally, the company transports, stores, and distributes refined products, NGLs, and crude oil, as well as conducts commodity-related activities, including liquids blending and marketing activities. It serves integrated and independent exploration and production companies; other NGL and natural gas gathering and processing companies; crude oil and natural gas production companies; utilities; industrial companies; natural gasoline distributors; propane distributors; municipalities; ethanol producers; petrochemical, refining, and marketing companies; and heating fuel users, refineries, and exporters. ONEOK, Inc. was founded in 1906 and is headquartered in Tulsa, Oklahoma.

Hess Corporation, an exploration and production company, explores, develops, produces, purchases, transports, and sells crude oil, natural gas liquids (NGLs), and natural gas. The company operates in two segments, Exploration and Production, and Midstream. It conducts production operations primarily in the United States, Guyana, the Malaysia/Thailand Joint Development Area, and Malaysia; and exploration activities principally offshore Guyana, the U.S. Gulf of Mexico, and offshore Suriname and Canada. The company is also involved in gathering, compressing, and processing natural gas; fractionating NGLs; gathering, terminaling, loading, and transporting crude oil and NGL through rail car; and storing and terminaling propane, as well as providing water handling services primarily in the Bakken Shale plays in the Williston Basin area of North Dakota. The company was incorporated in 1920 and is headquartered in New York, New York.

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.

UGI Corporation, together with its subsidiaries, distributes, stores, transports, and markets energy products and related services in the United States and internationally. The company operates through four segments: AmeriGas Propane, UGI International, Midstream & Marketing, and UGI Utilities. It distributes propane to approximately 1.3 million residential, commercial/industrial, motor fuel, agricultural, and wholesale customers through 1,400 propane distribution locations. The company distributes liquefied petroleum gases (LPG) to residential, commercial, industrial, agricultural, wholesale and automobile fuel customers; and provides logistics, storage, and other services to third-party LPG distributors. In addition, it engages in the retail sale of natural gas, liquid fuels, and electricity to approximately 12,400 residential, commercial, and industrial customers at 42,000 locations. Further, the company distributes natural gas to approximately 677,000 customers in eastern and central Pennsylvania counties through its distribution system of approximately 12,500 miles of gas mains; and supplies electricity to approximately 62,600 customers in northeastern Pennsylvania through 2,560 miles of lines and 14 substations. Additionally, it operates electric generation facilities, which include coal-fired, landfill gas-fueled, solar-powered, and natural gas-fueled facilities; a natural gas liquefaction, storage, and vaporization facility; propane storage and propane-air mixing stations; and rail transshipment terminals. It manages natural gas pipeline and storage contracts; develops, owns, and operates pipelines, gathering infrastructure, and gas storage facilities. UGI Corporation was incorporated in 1882 and is headquartered in King of Prussia, Pennsylvania.

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.

Transportadora de Gas del Sur S.A. engages in transportation of natural gas, and production and commercialization of natural gas liquids in Argentina and internationally. The company operates through four segments: Natural Gas Transportation Services; Liquids Production and Commercialization; Midstream; and Telecommunications. The Natural Gas Transportation segment transports natural gas through pipeline system to distribution companies, power plants, and industrial customers. It provides operation and maintenance services for the natural gas transportation facilities. The Liquids Production and Commercialization segment produces and commercializes natural gas liquids, such as ethane, liquid petroleum gas, natural gasoline, propane, and butane. This segment offers certain related services comprising reception, storage, and dispatch of the liquids. The Midstream segment provides natural gas conditioning services; treatment, removal of impurities and natural gas compression, including the collection and transport of natural gas; and inspection and maintenance of pipelines and compressor plants services. In addition, this segment offers steam generation for electricity production and management services for expansion works and steam generation for the production of electricity. The Telecommunications segment offers data transmission services through a network of digital terrestrial radio relay. It serves residential, commercial, industrial, and electric power generation end users. The company was incorporated in 1992 and is headquartered in Buenos Aires, Argentina. Transportadora de Gas del Sur S.A. is a subsidiary of Compañía de Inversiones de Energía S.A.