Hong Kong's securities regulator on Wednesday approved four cryptocurrency exchanges in the city's latest effort to stay competitive in a race to become a global centre for digital asset trading. Hong Kong has been promoting itself as a hub for assets such as cryptocurrencies in a effort to maintain its attractions as a financial centre. The Hong Kong Securities and Futures Commission said it had granted licences to Accumulus GBA Technology (Hongkong) Co., DFX Labs Company, Hong Kong Digital Asset EX, and Thousand Whales Technology (BVI).