HONG KONG, Dec 31 (Reuters) - The Hong Kong dollar firmed to as high as 7.7826 per U.S. dollar on Tuesday, its strongest since May 2017.

The Hong Kong dollar hit a five-month high earlier this month as months of anti-government protests in the city eased and investment inflows from China picked up. A global unwinding of long positions in the greenback also helped rouse the normally sleepy currency into its sharpest rally in more than a year.

Hong Kong’s currency is pegged to the greenback at a tight range of 7.75-7.85 per dollar and the city’s monetary policy moves in lock-step with the United States.