Fangda Carbon was the 11th most-traded common stock in the world on Friday, despite a $8.4-billion market capitalisation that failed to crack the global top 1,500. Its turnover exceeded that of JPMorgan Chase, which has a market value of $331 billion. The trading session was particularly volatile. After climbing as much as 8.9 per cent, the stock tumbled suddenly in the final hour of trading to close with a 7.1 per cent loss. The Shanghai Stock Exchange said it would take disciplinary action if the unusual trading in Fangda Carbon persists.