Bulent Ayhan Berilgen

Calpine Corp. operates as power generation company, which engages in the ownership and operation of natural-gas fired and geothermal power plants. It sells power and related services to wholesale customers who include commercial and industrial end-users, state and regional wholesale market operators, and retail customers. The company was founded by Peter Cartwright in June 1984 and is headquartered in Houston, TX.

Contango Oil & Gas Co. is an oil and natural gas company. The firm engages in the exploration, development, production and acquisition of crude oil and natural gas properties. Its operation focuses in Permian Basin, South Texas, Southeast Texas East Texas, Wyoming, and Gulf of Mexico. The company was founded by Kenneth R. Peak on August 7, 1986 and is headquartered in Fort Worth, TX.

Patara Oil & Gas LLC engages in acquisition, development and production of natural gas and crude oil properties. The company is headquartered in Dallas, TX.

Part of Chevron Corp., Rosetta Resources Operating LP sells natural gas. The private company is based in Houston, TX.

Rosetta Resources Inc. is an independent oil and gas exploration company, which engages in the acquisition and development of onshore energy resources in the U.S. The company also involves in the purchasing of new undeveloped leases, acquiring oil and gas producing properties and drilling prospects from third parties. Its operations are primarily located in the South Texas, including Eagle Ford shale and in the Southern Alberta Basin in Northwest Montana. The company was founded in June 2005 and is headquartered in Houston, TX.

Forest Oil Corp. is an independent oil and gas company, engaged in the acquisition, exploration, development and production of natural gas and liquids in the United States and selected international locations. The company's reserves and operational areas are in the Texas Panhandle, the Eagle Ford Shale in South Texas, and the Ark-La-Tex area. Its core operational areas consist of drilling projects that have exposure to oil, natural gas, and natural gas liquids. Forest Oil was founded in 1916 and is headquartered in Denver, CO.

Castleton Commodities International LLC provides commodities marketing and merchandising services. The firm markets physical commodities including natural gas, natural gas liquids, refined products, crude oil, fuel oil, freight, petrochemicals, electric power and coal and financial instruments related to commodities. The company was founded in 1997 and is headquartered in Stamford, CT.