(Yicai Global) July 17 -- China's mainland stock markets tailed off this afternoon as a drop in speculative buying burned through almost all of the major index's morning gains.

The Shanghai Composite Index closed down 0.2 percent at 2,931.69, while the Shenzhen Component Index ended 0.2 percent higher at 9,302.00. The ChiNext Price Index, which tracks growth enterprises listed in Shenzhen, finished up 0.32 percent at 1,550.22.