The USD is the base currency, and the HKD is the counter currency. The USD/HKD currency pair is an exotic couple, with a small trading volume as opposed to the major forex pairs.
The USD dates back to 1792, when the United States Congress created the US dollar as the official country’s currency. It serves as legal tender in many countries, and it is the most widely used currency in the world both in circulation and reserve. The US dollar form the majors as it pairs with all main currencies in the foreign exchange market (forex). The Hong Kong dollar is considered to be one of the world’s most traded currencies in the world. Hong Kong is one of the world’s leading international financial centers and has a major capitalist service economy characterised by low taxation and free trade. Despite the 2009 crisis in economic, the country has recovered well. Hong Kong and mainland China use different currencies, with the first using the Hong Kong dollar and the latter the Chinese yuan. In addition, merchants in Hong Kong do not freely accept the yuan.