William Kellstrom

MarkWest Hydrocarbon LLC provides natural gas processing services. It also provides transportation, fractionation, and storage of natural gas liquids and transportation of crude oil. The company was founded by John M. Fox in April 1998 and is headquartered in Denver, CO.

MarkWest Energy Partners LP engages in the business of gathering, processing and transportation of natural gas; the transportation, fractionation, storage and marketing of natural gas liquids; and the gathering and transportation of crude oil. It operates through four segments: Marcellus, Utica, Northeast and Southwest. The Southwest segment includes the operations of processing facilities in Corpus Christi, Texas. The Northeast segment assets include the Kenova, Boldman, Cobb, Kermit and the Langley natural gas processing complexes, NGL pipeline and Siloam NGL fractionation facility. The Marcellus segment includes gathering, processing and fractionation infrastructure in the liquids-rich area of the Marcellus Shale The Utica segment provides fractionation services. The company was founded in January 2002 and is headquartered in Denver, CO.

Part of Marathon Petroleum Corp., MarkWest Energy GP LLC is a company that provides oil and gas field services not elsewhere classified. The company is based in Englewood, CO. The company was founded by John C. Mollenkopf.

CenterPoint Energy Resources Corp. engages in owning and operating natural gas distribution systems. It also offers variable and fixed-price physical natural gas supplies primarily to commercial and industrial customers and gas utilities. It operates through the following segments: Natural Gas Distribution, Energy Services, Midstream Investments, and Other Operations. The Natural Gas Distribution segment refers to the intrastate natural gas sales and natural gas transportation and distribution for residential, commercial, industrial, and institutional customers. The Energy Services segment represents the company’s non-rate regulated gas sales and services operations. The Midstream Investments segment includes equity investment in Enable. The Other Operations segment provides unallocated corporate costs and inter-segment eliminations. CenterPoint Energy Resources was founded in 1882 and is headquartered in Houston, TX.

Enron Corp. provides energy related services

Tenaska Marketing Ventures, Inc. develops, constructs, owns, and operates non-utility generation and cogeneration plants. It offers natural gas, biofuels, and electric power. The firm offers risk management services in asset acquisition and management, power marketing, fuel supply, gas transportation systems, biofuels marketing, and electric transmission development. The company was founded by Howard L. Hawks, Thomas E. Hendricks, and William A. Kellstrom in 1987 and is headquartered in Omaha, NE.