BEIJING -- China's stock index futures closed down on Wednesday with the contract for September, the most actively traded, down 0.49 percent from the previous trading day to 2,800.4 points.

The October contract closed down 0.6 percent to 2,808.2 points. The December contract fell 0.47 percent to 2,817 points, while the March contract for 2012 was down 0.39 percent to finish at 2,848 points.

The stock-index contracts, agreements to buy or sell the Hushen 300 Index at a preset value on an agreed date, are designed to allow investors to bet on and profit from both gains and declines in the market.

The index futures was launched at the China Financial Futures Exchange (CFFEX) and started trading from April 16, 2010. The CFFEX has set the base value for all the four contracts at 3,399 points.