China’s stocks tumbled, with the benchmark index falling the most since February 2007, amid concern a three-week rally sparked by unprecedented government intervention is unsustainable. The Shanghai Composite Index plunged 8.5 percent to 3,725.56 at the close, with 75 stocks dropping for each one that rose. PetroChina Co., long considered a target of state-linked market support funds, tumbled by a record 9.6 percent. The rout dented investor confidence from Hong Kong to Taiwan and Indonesia, helping send the MSCI Emerging Markets Index to a two-year low. Monday’s retreat shattered the sense of calm that had fallen ... (full story)