China’s futures trading houses were advised to limit overseas speculation due to government concerns about volatility in the global commodities markets, the Wall Street Journal reported. The warning was issued by Jiang Yang, assistant to the chairman of the China Securities Regulatory Commission, according to a statement issued by the regulator. It came in response to a global commodities selloff that has pushed down prices and shaken international markets. Twenty-five Chinese futures houses are permitted to trade overseas. It is an open secret that they take risky bets on copper futures in an attempt to profit from difference in prices between Shanghai and London. However, domestic futures exchanges have come under pressure because there are daily limits on the movement of prices. Other exchanges are not subject to the same rules and price movements have been larger than those permitted in China.