Chevron Corporation, through its subsidiaries, engages in the integrated energy and chemicals operations in the United States and internationally. The company operates in two segments, Upstream and Downstream. The Upstream segment is involved in the exploration, development, production, and transportation of crude oil and natural gas; processing, liquefaction, transportation, and regasification of liquefied natural gas; transportation of crude oil through pipelines; transportation, storage, and marketing of natural gas; and carbon capture and storage, as well as a gas-to-liquids plant. The Downstream segment refines crude oil into petroleum products; markets crude oil, refined products, and lubricants; manufactures and markets renewable fuels, commodity petrochemicals, plastics for industrial uses, and fuel and lubricant additives; and transports crude oil and refined products by pipeline, marine vessel, motor equipment, and rail car. The company was formerly known as ChevronTexaco Corporation and changed its name to Chevron Corporation in 2005. Chevron Corporation was founded in 1879 and is headquartered in San Ramon, California.

Shell plc operates as an energy and petrochemical company Europe, Asia, Oceania, Africa, the United States, and Rest of the Americas. The company operates through Integrated Gas, Upstream, Marketing, Chemicals and Products, and Renewables and Energy Solutions segments. It explores for and extracts crude oil, natural gas, and natural gas liquids; markets and transports oil and gas; produces gas-to-liquids fuels and other products; and operates upstream and midstream infrastructure to deliver gas to market. The company also markets and trades natural gas, liquefied natural gas (LNG), crude oil, electricity, carbon-emission rights; and markets and sells LNG as a fuel for heavy-duty vehicles. In addition, it trades in and refines crude oil and other feed stocks, such as low-carbon fuels, lubricants, bitumen, sulphur, gasoline, diesel, aviation fuel, and marine fuel; produces and sells petrochemicals for industrial use; and manages oil sands activities. Further, the company produces base chemicals comprising ethylene, propylene, and aromatics, as well as intermediate chemicals, such as styrene monomer, propylene oxide, solvents, detergent alcohols, ethylene oxide, and ethylene glycol. Additionally, it generates electricity through wind and solar resources; produces and sells hydrogen; and provides electric vehicle charging services. The company was formerly known as Royal Dutch Shell plc and changed its name to Shell plc in January 2022. Shell plc was founded in 1907 and is headquartered in London, the United Kingdom.

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.

Calumet, Inc. manufactures, formulates, and markets a diversified slate of specialty branded products and renewable fuels to various consumer-facing and industrial markets in North America and internationally. It operates through Specialty Products and Solutions; Montana/Renewables; and Performance brands segments. The Specialty Products and Solutions segment offers various solvents, waxes, customized lubricating oils, white oils, petrolatums, gels, esters, and other products. The Montana/Renewables segment focuses on processing renewable feedstocks into renewable diesel, sustainable aviation fuel, renewable hydrogen, renewable natural gas, renewable propane, and renewable naphtha. It also processes Canadian crude oil into conventional gasoline, diesel, jet fuel, and specialty grades of asphalt. The Performance Brands segment blends, packages, and markets high performance products through Royal Purple, Bel-Ray, and TruFuel brands. The company serves wholesale distributors and retail chains. Calumet, Inc. was founded in 1919 and is headquartered in Indianapolis, Indiana.

Green Plains Inc. produces low-carbon fuels in the United States and internationally. It operates through three segments: Ethanol Production, Agribusiness and Energy Services, and Partnership. The Ethanol Production segment produces ethanol, distillers grains, and ultra-high protein and renewable corn oil. The Agribusiness and Energy Services segment engages in the grain procurement, handling and storage, commodity marketing business; and trading of ethanol, distiller grains, renewable corn oil, grain, natural gas, and other commodities in various markets. This segment also provides grain drying and storage services to grain producers. The Partnership segment offers fuel storage and transportation services. It operates 24 ethanol storage facilities; two fuel terminal facilities; and a fleet of approximately 2,180 leased railcars. The company was formerly known as Green Plains Renewable Energy, Inc. and changed its name to Green Plains Inc. in May 2014. Green Plains Inc. was incorporated in 2004 and is headquartered in Omaha, Nebraska.

Aemetis, Inc. operates as a renewable natural gas and renewable fuels company. It operates through three segments: California Ethanol, California Dairy Renewable Natural Gas, and India Biodiesel. The company focuses on the operation, acquisition, development, and commercialization of technologies to produce low and negative carbon intensity renewable fuels that replace fossil-based products. In addition, it produces and sells ethanol; and wet distillers grains, distillers corn oil, and condensed distillers solubles to dairies and feedlots as animal feed. Further, the company markets and supplies USP alcohol and hand sanitizer; and produces renewable natural gas, as well as distilled biodiesel from various vegetable oil and animal waste feedstocks. Additionally, it researches and develops conversion technologies using waste feedstocks to produce biofuels and biochemicals. Furthermore, it sells biodiesel primarily to government oil marketing companies. Aemetis, Inc. is headquartered in Cupertino, California.

NuStar Energy L.P. engages in the transportation, terminalling, and storage of petroleum products and renewable fuels, and transportation of anhydrous ammonia in the United States and internationally. It operates through three segments: Pipeline, Storage, and Fuels Marketing. The Pipeline segment engages in the transportation of refined products, crude oil, and anhydrous ammonia. The Storage segment offers storage, handling, and other services for refined products, crude oil, specialty chemicals, renewable fuels, and other liquids. The Fuels Marketing segment provides bunkering operations in the Gulf Coast; and blending operations with Central East System primarily for ship owners, marketers, and traders. The company was incorporated in 1999 and is headquartered in San Antonio, Texas.