One of the world's legendary investors is upping his bet on Argentina's shale oil and gas industry in a show of confidence for shale production in South America's largest unconventional prize - and a big boost for both supermajors and smaller players making big waves in the heart of new discovery areas. George Soros has doubled his stake in YPF SA, the state-owned oil company in Argentina, which sits atop some of the world's largest shale oil and gas resources, and is about to get even larger following a new discovery over the last couple of weeks of a second key shale play.