Targa Resources Corp., together with its subsidiary, Targa Resources Partners LP, owns, operates, acquires, and develops a portfolio of complementary domestic midstream infrastructure assets in North America. It operates in two segments, Gathering and Processing, and Logistics and Transportation. The company is involved in gathering, compressing, treating, processing, transporting, and selling natural gas; storing, fractionating, treating, transporting, and selling natural gas liquids (NGL) and NGL products, including services to liquefied petroleum gas exporters; and gathering, storing, terminaling, purchasing, and selling crude oil. It is also involved in the purchase and resale of NGL products; and sale of propane, as well as provision of related logistics services to multi-state retailers, independent retailers, and other end-users. In addition, the company offers NGL balancing services; and transportation services to refineries and petrochemical companies in the Gulf Coast area, as well as purchases, markets, and resells natural gas. As of December 31, 2023, it leased and managed approximately 605 railcars; 137 tractors; and 6 vacuum trucks and 2 pressurized NGL barges. Targa Resources Corp. was incorporated in 2005 and is headquartered in Houston, Texas.

Western Midstream Partners, LP, together with its subsidiaries, operates as a midstream energy company primarily in the United States. It is involved in gathering, compressing, treating, processing, and transporting natural gas; gathering, stabilizing, and transporting condensate, natural gas liquids (NGLs), and crude oil; and gathering and disposing produced water. The company also buys and sells natural gas, NGLs, and condensate. It operates assets located in Texas, New Mexico, the Rocky Mountains, and North-central Pennsylvania. Western Midstream Holdings, LLC operates as the general partner of the company. The company was formerly known as Western Gas Equity Partners, LP and changed its name to Western Midstream Partners, LP in February 2019. Western Midstream Partners, LP was incorporated in 2007 and is based in The Woodlands, Texas.

Plains All American Pipeline, L.P., through its subsidiaries, engages in the pipeline transportation, terminaling, storage, and gathering of crude oil and natural gas liquids (NGL) in the United States and Canada. The company operates through two segments, Crude Oil and NGL. The Crude Oil segment offers gathering and transporting crude oil through pipelines, gathering systems, trucks, and on barges or railcars. This segment provides terminaling, storage, and other facilities-related services, as well as merchant activities. The NGL segment is involved in natural gas processing and NGL fractionation, storage, transportation, and terminaling. This segment also includes ethane, propane, normal butane, iso-butane, and natural gasoline derived from natural gas production and processing activities, as well as crude oil refining processes. Its NGL components are used for various applications, such as heating, engine, and industrial fuels. The company was founded in 1981 and is headquartered in Houston, Texas. Plains All American Pipeline, L.P. operates as a subsidiary of Plains GP Holdings, L.P.

EnLink Midstream, LLC provides midstream energy services in the United States. The company operates through Permian, Louisiana, Oklahoma, North Texas, and Corporate segments. It is involved in gathering, compressing, treating, processing, transporting, storing, and selling natural gas; fractionating, transporting, storing, and selling natural gas liquids; and gathering, transporting, stabilizing, storing, trans-loading, and selling crude oil and condensate, as well as providing brine disposal services. In addition, the company's midstream energy asset network includes natural gas processing plants; fractionators; barge and rail terminals; product storage facilities; and brine disposal wells. EnLink Midstream, LLC was incorporated in 2013 and is based in Dallas, Texas.

Plains GP Holdings, L.P., through its subsidiary, Plains All American Pipeline, L.P., owns and operates midstream infrastructure systems in the United States and Canada. It operates in two segments, Crude Oil and Natural Gas Liquids (NGLs). The company engages in the gathering and transporting crude oil and NGLs using pipelines, gathering systems, and trucks. It engages in the loading and unloading services at terminals; NGL fractionation and isomerization services; and natural gas and condensate processing services. The company offers logistics services to producers, refiners, and other customers. PAA GP Holdings LLC operates as a general partner of the company. Plains GP Holdings, L.P. was incorporated in 2013 and is headquartered in Houston, Texas.

Natural Gas Services Group, Inc. provides natural gas compression equipment and services to the energy industry in the United States. It engineers and fabricates, operates, rents, and maintains natural gas compressors for oil and natural gas production and plant facilities. It also designs, fabricates, and assembles compressor units for rental or sale; and designs, manufactures, and sells a line of reciprocating natural gas compressor frames, cylinders, and parts. In addition, the company offers flare stacks and related ignition and control devices for the onshore and offshore incineration of gas compounds, such as hydrogen sulfide, carbon dioxide, natural gas, and liquefied petroleum gases. Further, it provides aftermarket services for its compressor and flare sales business; and exchange and rebuild program for small horsepower screw compressors. It markets its products to exploration and production companies that utilize compressor units for artificial lift applications; and oil and natural gas exploration and production companies. Natural Gas Services Group, Inc. was incorporated in 1998 and is headquartered in Midland, Texas.

CSI Compressco LP provides contract services for natural gas compression and treating in the United States, Latin America, Canada, Egypt, and internationally. The company offers natural gas compression services through low-, medium-, and high-horsepower compressor packages for oil and natural gas production, gathering, artificial lift, transmission, processing, and storage. It also provides treating services for natural gas producers and midstream companies, including providing equipment for lease or sale, equipment installation services, and the operation of equipment for removal of contaminants from a natural gas stream, and natural gas cooling to reduce the temperature of produced gas and liquids; well monitoring and sand separation services; and operation, maintenance, overhaul, and reconfiguration services for compression equipment. In addition, the company sells engine parts, compressor package parts, and other parts manufactured by third-party suppliers. The company was formerly known as Compressco Partners, L.P. and changed its name to CSI Compressco LP in December 2014. CSI Compressco LP was incorporated in 2008 and is headquartered in The Woodlands, Texas.

Summit Midstream Partners, LP focuses on owning, developing, and operating midstream energy infrastructure assets primarily shale formations in the continental United States. The company provides natural gas gathering, compression, treating, and processing services, as well as crude oil and produced water gathering and freshwater delivery services. Its assets include Summit Utica system comprising the Utica and Point Pleasant shale formations in southeastern Ohio; Mountaineer Midstream system that includes the Marcellus shale in the Appalachian Basin in West Virginia; Polar and Divide system includes the Bakken and Three Forks shale formations in northwestern North Dakota; Niobrara G&P system, which comprises the Niobrara and Codell shale formations located near Hereford, Colorado. The company's assets also include Double E, a 135 mile interstate natural gas transmission pipeline; Grand River system that gathers natural gas produced from the Mancos and Niobrara shale formations in western Colorado; and DFW Midstream system comprising the Barnett Shale formation located in north-central Texas. In addition, it owns an ownership interest in Ohio Gathering, which owns and operates natural gas gathering and condensate stabilization facility in the Utica Shale in southeastern Ohio. It serves natural gas and crude oil producers. Summit Midstream GP, LLC operates as a general partner of the company. Summit Midstream Partners, LP was founded in 2009 and is based in Houston, Texas.