AlQa'dah 5, 1436, Aug 20, 2015, SPA -- China stocks tumbled again in late trading on Thursday, underscoring fragile investor confidence in the market as worries about the world's second largest economy persist, Reuters reported. Trading volumes were thin, suggesting many investors stayed on the sidelines. Shares were marginally lower in the morning, as statements by a slew of companies that the government had invested in them boosted some counters. But in mid-afternoon, prices began to drop. The CSI300 index of the largest listed companies in Shanghai and Shenzhen fell 3.2 percent, to 3,761.45, while the Shanghai Composite Index lost 3.4 percent, to 3,664.29 points The SSEC is now down about 7 percent since China devalued the yuan by nearly 2 percent on Aug. 11.