Hong Kong stocks plummet on opening      

The Hang Seng Index sank 2.72 percent, or 886.22 points, to 31,715.56.

And the benchmark Shanghai Composite Index fell 1.46 percent, or 50.41 points, to 3,411.67 while the Shenzhen Composite Index, which tracks stocks on China's second exchange, dropped 1.40 percent, or 25.54 points, to 1,795.99.