The Chinese yuan slipped to a six-year low against a strong US dollar. On Friday, China's central bank fixed the daily yuan dollar midpoint at 6.7558. That's 247 basis points lower than the previous setting, the biggest decline since the end of August.

Analysts say the yuan's weakness is a result of a stronger US dollar. New York Federal Reserve Bank President William Dudley on Thursday said a rate hike will happen later this year, if the economy stays on its current trajectory.

And the dollar index confirms that comment. Since the beginning of October, the yuan has lost about 1 percent against the dollar since the end of September.