Chesapeake Energy Corp., an Oklahoma-based natural gas producer, revealed in its quarterly filing that it had sold off all its shares of Clean Energy Fuels Corp. Clean Energy Fuels Corp. is a nationwide supplier of natural gas fuel for transportation. Clean Energy Fuels Corp. is currently backed by T. Boone Pickens, a Texas oil magnate.

According to the Chesapeake, the value of its US$10 million investment in Clean Energy Fuels Corp. had increased by US$3 million before the company sold its entire stake last month. The US$13 million investment represented a 1.1% stake in Clean Energy Fuels Corp. A Clean Energy Fuels representative stated that Mr. Pickens together with Leonard Green & Partners bought Chesapeake's convertibles. Both investors also assumed a US$50 million investment committment. Pickens already owns a fifth of Clean Energy Fuels.

Clean Energy Fuels, at present, operates liquefied natural gas and compressed natural gas fueling stations across the United States.