BEIJING -- The ChiNext Index, tracking China's Nasdaq-style board of growth enterprises, tumbled 2.91 percent, or 39.24 points, to close at 1,311.23 points on Wednesday.

The index, together with the Shenzhen Component Index and the Shenzhen SME (small and medium-sized enterprises) Board Index, makes up the three core indices reflecting the performance of China's stocks listed on the Shenzhen Stock Exchange.

The ChiNext Board, which started trading on Oct 30, 2009, mainly lists high-tech companies and those with high growth potential.