Ample inventories and muted demand so far this winter heating season have turned portfolio managers bearish on European natural gas for the first time since September and benchmark prices are now down to a four-month low. At the end of last week, hedge funds and other money managers held a net short position in the Dutch TTF Natural Gas Futures, the benchmark for Europe’s gas trading, according to data from exchanges released on Wednesday and reported by Bloomberg. High inventories, eased fears of supply shortages, weak demand, and increased…