A months-long rally in China’s commodity futures may be coming to an end after the country’s exchanges took steps to crack down on speculative trading, according to the Financial Times. Futures for coal and iron ore that rallied sharply this year have gyrated this week following a dramatic rout on Friday evening after China’s three commodity exchanges increased margin requirements. “It ran up too much and the increased margin requirements by the exchanges are starting to bite,” said a trader at one house that has taken big bets on commodities futures this year. Iron ore futures on the Dalian exchange dropped by more than 6% to RMB 562 a tonne on Wednesday, although they are still up 75% since the start of the year.