The Shanghai Composite Index sank by 4.3% on Thursday to close at 1,909.94 points, Bloomberg reported. The index is now only 100 points clear of the 22-month low it reached on September 18, prior to the axing of stamp duty and the direct purchase of shares in several state-run banks by Central Huijin, an investment arm of China’s sovereign wealth fund. The CSI 300 Index, which tracks A-shares listed in Shanghai and Shenzhen, did it eclipse its previous losses, sinking 4.9% to 1,820.90, its lowest close since December 2006. Jiangxi Copper fell by the maximum-permitted 10% as copper and zinc prices floundered on the Shanghai Futures Exchange. Air China also fell 10% after forecasting a nine-month loss because of rising fuel costs and disruptions caused by national disasters and Olympics-related restrictions. CITIC Securities slipped 7.7% as more rival brokerages predicted severe losses for the first nine months.