The CSI300 index of the largest listed companies in Shanghai and Shenzhen ended up 3.2 percent for the day, but lost 21 percent for the month, its biggest decline since August 2009.
Trading was light throughout the month, as many investors are giving the market a wide berth, burnt not just by January's slump, which has taken indexes back to 2014 levels, but also last summer's 40 percent crash.