(Yicai Global) Dec. 21 -- Stock markets on the Chinese mainland closed down today after a slump in prices of heavyweight shares, pushing the Shanghai benchmark temporarily below the 2,500 milestone in afternoon trading.

The Shanghai Composite Index finished the day down 0.79 at 2,516.25, with traders swapping CNY101.4 billion (USD14.7 billion) worth of shares.

The Shenzhen Component Index closed 1.2 percent lower at 7,337.6, with a trading volume of almost CNY135 billion.

The ChiNext Price Index, which tracks growth enterprises in Shenzhen, ended down 0.61 percent at 1,270.30, with investors trading CNY39.7 billion worth of shares.