Hong Kong's de facto central bank is bidding farewell to its chief after a decade, starting the search for a successor at a time when the city faces an outlook made uncertain by the slowing Chinese economy and the trade war with the U.S.

Norman Chan, who has been the Chief Executive of the Hong Kong Monetary Authority since 2009, will retire on Oct. 1 at the end of his second five-year term, the government announced Thursday.

The HKMA's main task is defending the city's currency peg to the U.S. dollar, meaning the former British colony's monetary policy is imported from Washington even as its status as a center for trading in China's currency, the yuan, grows. Chan took office as Hong Kong was being buffeted by the global financial crisis and leaves it amid increasing vulnerability due to record property prices and the protectionist threat to the open trade that the city thrives on.