Hong Kong shares sank today, tracking a sell off on Wall Street ahead of a much anticipated federal reserve policy decision later in the week.

The Hang Seng Index Sank 1.39 percent, to 17,930.55.

However, the Shanghai Composite Index gained 0.26 percent, to 3,125.93, while the Shenzhen Composite Index on China's second exchange added 0.54 percent, to 1,921.48.