Commodities trader and investor TrailStone Group has purchased Cargill Inc's gas and power trading group, three sources familiar with the deal said this week. The move, first reported by Sparkspread, comes amid a reshuffling in the power and natural gas industry as private equity firms and hedge funds pour into the space, filling a void left by banks and other longtime players. The banks and others have been pulling back over the past several years as natural gas prices have reached lows not seen in a decade, due to abundant U.S. shale gas and increasingly strict capital requirements and regulations that have pressured banks to reduce their involvement in physical commodities markets.