Hedge fund managers reduced net-long positions across 18 US commodities futures and options by 9.3% in the week ended April 10, the biggest reduction since December 20, signaling that concern is mounting over a slowdown in Chinese growth, Bloomberg reported. Copper holdings dived 84%, the biggest drop since November. The Standard & Poor’s GSCI Spot Index of 24 raw materials fell 1% last week, led by natural gas, which hit a 10-year low, as well as sugar and copper. Commodities will “drift lower” this quarter as central banks refrain from adding further stimulus, UBS AG predicted in a note last week. Worldwide growth is expected to be a “little softer” than expected, Bill Greiner, chief investment officer of Mariner Wealth Advisors said. Government data showed that China’s economy grew 8.1% year-on-year last quarter, below the estimate of 8.4% of economists surveyed by Bloomberg. China accounts for 40% of the world’s copper consumption and 11% of its oil demand.