(Yicai Global) Sept. 7 -- China's mainland stock markets started the day slightly lower this morning as investors are cautious amid volatility overseas.

The Shanghai Composite Index opened 0.16 percent lower at 3,349.92. The bourse's Nasdaq-like Star Market Board 50 Index, or Star 50, slid 0.2 percent to 1,387.49.

The Shenzhen Component Index stood at 13,633.51, down 0.17 percent. The ChiNext Price Index, which tracks growth enterprises listed in Shenzhen, fell 0.12 percent to 2,728.74.

Editor: Emmi Laine