Marathon Petroleum Corporation, together with its subsidiaries, operates as an integrated downstream energy company primarily in the United States. The company operates through Refining & Marketing, and Midstream segments. The Refining & Marketing segment refines crude oil and other feedstocks at its refineries in the Gulf Coast, Mid-Continent, and West Coast regions of the United States; and purchases refined products and ethanol for resale and distributes refined products, including renewable diesel, through transportation, storage, distribution, and marketing services. Its refined products include transportation fuels, such as reformulated gasolines and blend-grade gasolines; heavy fuel oil; and asphalt. This segment also manufactures propane and petrochemicals. It sells refined products to wholesale marketing customers in the United States and internationally, buyers on the spot market, and independent entrepreneurs who operate primarily Marathon branded outlets, as well as through long-term fuel supply contracts to direct dealer locations primarily under the ARCO brand. The Midstream segment transports, stores, distributes, and markets crude oil and refined products through refining logistics assets, pipelines, terminals, towboats, and barges; gathers, processes, and transports natural gas; and gathers, transports, fractionates, stores, and markets natural gas liquids. Marathon Petroleum Corporation was founded in 1887 and is headquartered in Findlay, Ohio.

Phillips 66 operates as an energy manufacturing and logistics company in the United States, the United Kingdom, Germany, and internationally. It operates through four segments: Midstream, Chemicals, Refining, and Marketing and Specialties (M&S). The Midstream segment transports crude oil and other feedstocks; delivers refined petroleum products to market; provides terminaling and storage services for crude oil and refined petroleum products; transports, stores, fractionates, exports, and markets natural gas liquids; provides other fee-based processing services; and gathers, processes, transports, and markets natural gas. The Chemicals segment produces and markets ethylene and other olefin products; aromatics and styrenics products, such as benzene, cyclohexane, styrene, and polystyrene; and various specialty chemical products, including organosulfur chemicals, solvents, catalysts, and chemicals used in drilling and mining. The Refining segment refines crude oil and other feedstocks into petroleum products, such as gasolines, distillates, aviation, and renewable. The M&S segment purchases for resale and markets refined petroleum products, including gasolines, distillates, and aviation fuels. This segment also manufactures and markets specialty products, such as base oils and lubricants. Phillips 66 was founded in 1875 and is headquartered in Houston, Texas.

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.

Valero Energy Corporation manufactures, markets, and sells petroleum-based and low-carbon liquid transportation fuels and petrochemical products in the United States, Canada, the United Kingdom, Ireland, Latin America, Mexico, Peru, and internationally. It operates through three segments: Refining, Renewable Diesel, and Ethanol. The company produces California Reformulated Gasoline Blendstock for Oxygenate Blending and Conventional Blendstock for Oxygenate Blending gasolines, CARB diesel, diesel, jet fuel, heating oil, and asphalt; feedstocks; aromatics; sulfur and residual fuel oil; intermediate oils; and sulfur, sweet, and sour crude oils. It sells its refined products through wholesale rack and bulk markets; and through outlets under the Valero, Beacon, Diamond Shamrock, Shamrock, Ultramar, and Texaco brands. The company owns and operates renewable diesel and ethanol plants, as well as produces renewable diesel and naphtha under the Diamond Green Diesel brand name. In addition, it offers ethanol and various co-products, including dry distiller grains, syrup, and inedible distillers corn oil to animal feed customers. The company was formerly known as Valero Refining and Marketing Company and changed its name to Valero Energy Corporation in August 1997. Valero Energy Corporation was founded in 1980 and is headquartered in San Antonio, Texas.

Sunoco LP, together with its subsidiaries, distributes and retails motor fuels in the United States. It operates through two segments: Fuel Distribution and Marketing, and All Other. The Fuel Distribution and Marketing segment purchases motor fuel, as well as other petroleum products, such as propane and lubricating oil from independent refiners and oil companies and supplies it to company-operated retail stores, independently operated commission agents, and retail stores, as well as other commercial customers, including unbranded retail stores, other fuel distributors, school districts, municipalities, and other industrial customers. It owns and operates retail stores under the APlus and Aloha Island Mart brand names; and offers food, beverages, snacks, grocery and non-food merchandise, motor fuels, and other services. The All Other segment includes partnership credit card services, franchise royalties, and retail operations; and offers credit card processing, car washes, lottery, automated teller machines, money order, prepaid phone cards, and wireless services. The company was formerly known as Susser Petroleum Partners LP and changed its name to Sunoco LP in 2014. Sunoco LP was founded in 1886 and is headquartered in Dallas, Texas.

Delek Logistics Partners, LP provides gathering, pipeline, transportation, and other services for crude oil, intermediates, refined products, natural gas, storage, wholesale marketing, terminalling water disposal and recycling customers in the United States. The Gathering and Processing segment consists of pipelines, tanks, and offloading facilities that provide crude oil and natural gas gathering and processing, water disposal and recycling, and storage services, as well as crude oil transportation services to third parties. The Wholesale Marketing and Terminalling segment includes refined products terminals and pipelines in Texas, Tennessee, and Arkansas. This segment provides marketing services for the refined products and terminalling services at refined products terminals to independent third parties. The Storage and Transportation segment comprises tanks, offloading facilities, trucks, and ancillary assets, which provide crude oil, intermediate, and refined products transportation and storage services. Delek Logistics GP, LLC serves as the general partner of the company. Delek Logistics Partners, LP was incorporated in 2012 and is headquartered in Brentwood, Tennessee. Delek Logistics Partners, LP operates as a subsidiary of Delek US Holdings, Inc.

Par Pacific Holdings, Inc. owns and operates energy and infrastructure businesses. The company operates through Refining, Retail, and Logistics segments. The Refining segment owns and operates refineries that produce gasoline, distillate, asphalt, and other products primarily for consumption in Kapolei, Hawaii, Newcastle, Wyoming, Tacoma, Washington, and Billings, Montana. The Retail segment operates fuel retail outlets, which sell merchandise, such as soft drinks, prepared foods, and other sundries in Hawaii under the Hele, 76, and nomnom brands; and gasoline, diesel, and retail merchandise in Washington and Idaho. The Logistics segment owns and operates terminals, pipelines, single point mooring, marine vessels, storage facilities, loading and truck racks, and rail facilities to distribute ethanol, petroleum, and refined products throughout Hawaii, the United States West Coast, Washington, the Dakotas, and Wyoming; and a jet fuel storage facility and pipeline that serves Ellsworth Air Force Base in South Dakota. It also holds interest in refined products pipeline. In addition, the company owns and operates a marine terminal, a unit train-capable rail loading terminal; a truck rack, and a proprietary pipeline that serves Joint Base Lewis McChord. The company was formerly known as Par Petroleum Corporation and changed its name to Par Pacific Holdings, Inc. in October 2015. Par Pacific Holdings, Inc. was incorporated in 1984 and is headquartered in Houston, Texas.

NGL Energy Partners LP engages in the transportation, storage, blending, and marketing of crude oil, natural gas liquids, refined products/renewables, and water solutions. The company operates through three segments: Water Solutions, Crude Oil Logistics, and Liquids Logistics. The Water Solutions segment transports, treats, recycles, and disposes produced and flowback water generated from crude oil and natural gas production; aggregates and sells recovered crude oil; disposes solids, such as tank bottoms, and drilling fluid and muds, as well as performs truck and frac tank washouts; and sells produced water for reuse and recycle, and brackish non-potable water. The Crude Oil Logistics segment purchases crude oil from producers and marketers, and transports it to refineries for resale at pipeline injection stations, storage terminals, barge loading facilities, rail facilities, refineries, and other trade hubs; and provides storage, terminaling, and transportation services through pipelines and storage tanks. The Liquids Logistics segment supplies natural gas liquids, refined petroleum products, and biodiesel to commercial, retail, and industrial customers in the United States and Canada through its 23 terminals, third-party storage and terminal facilities, and nine common carrier pipelines, as well as through a fleet of leased railcars. This segment also provides services for marine exports of butane through its facility located in Chesapeake, Virginia; and owns a propane pipeline in Michigan. NGL Energy Holdings LLC serves as the general partner of the company. The company was founded in 1940 and is headquartered in Tulsa, Oklahoma.