When news spread on Thursday that brokers tightened margin trading requirements and that Chinese government's investment fund, Central Huijin, decreased holdings in two state-owned banks, the Shanghai Composite Index .SSEC slumped 6.5 percent. The abrupt drop sent shudders through a market that had rocketed 140 percent since mid-2014 to hit its highest level since the global financial crisis struck in 2008. The index flitted in and out of positive territory on Friday as investors were still wondering whether this was simply a correction caused by policymakers quietly tugging on the reins, or whether it spelt the end ... (full story)