Rating agency Standard & Poor's (S&P) affirmed China's sovereign debt rating at 'AA-' but downgraded the outlook to 'negative' from 'stable'. The agency said that the downward revision was driven by a slower-than-expected pace of the implementation of reforms.

"Economic and financial risks to the Chinese government's creditworthiness are gradually increasing," the agency noted.

S&P affirmed Hong Kong's rating at 'AAA'. The agency also downgraded the outlook to 'negative' from 'stable'.