Japan ’s third-largest trading house, said it booked another writedown on its investment in oil and gas producer Samson Investment Co., as its bet on the U.S. shale boom sours. The latest impairment of 29 billion yen ($279 million) follows charges of about 33 billion yen reported by the Tokyo-based company last year. Itochu has now written down most of the 78 billion yen, worth $1.04 billion at the time, it paid in 2011 for a 25 percent stake in family-owned Samson. The development of shale, which involves extracting hydrocarbons from rock formations through chemical injections, has slapped investors with writedowns in the last two years after U.S. gas prices fell to their lowest level in more than a decade in April 2012. BHP Billiton Ltd., the world’s largest mining company, in August 2012 announced a $2.8 billion writedown of its U.S. shale gas assets. Itochu joined a […]