The benchmark Shanghai Composite Index (SCI) rose 4.8% on Thursday, its biggest gain in six months, on the back of the securities regulator’s reassurance that it will promote a “stable and healthy” market, Bloomberg reported. The SCI closed at 2,845.02 points and, after three straight days of gains, has almost erased the 6.7% decline on August 31. The CSI 300 Index, which covers Shanghai and Shenzhen, gained 5.6% to 3,051.96. The volatility in the market is the result of concerns about policy tightening. China has recently sought to curb bank lending in a bid to prevent asset bubbles while industries such as steel and cement have been warned about potential overcapacity. However, analysts said that words of reassurance from the China Securities Regulatory Commission have prompted speculation that the government may take steps to support the market.