The government has embarked on multiple rounds of measures to cool the overheating property market in Hong Kong. They have levied extra duties on the purchase of property in Hong Kong to cool demand and have also imposed limits on banks’ mortgage lending to dampen the supply of credit for potential buyers and investors. The GovHK website contains all the information you would be required to know with regards to the Special Stamp Duty (SSD), Buyer's Stamp Duty (BSD), and new and old Ad Valorem Stamp Duty rates. The website also contains information on stamp duties relating to renting of a property. The link can be found below:
The Hong Kong Monetary Authority has issued guidelines and a chart which illustrate the various restrictions imposed on mortgage lending. The FAQ section provides the necessary information and the link can be found below: