HKD is the ISO code of the Hong Kong dollar, the national currency of Hong Kong. Like the US dollar, HKD is subdivided into 100 cents.
However, unlike the US dollar and indeed many other currencies, Hong Kong dollars are printed by HSBC, the Bank of China and Standard Chartered under license from the Hong Kong Monetary Authority (Hong Kong’s central bank).
$20, $50, $100, $500 and $1000 dollar bills are printed by the above three institutions, each with a slightly differing design.
The only standardized Hong Kong dollar is the $10 dollar bill, which is printed by the Bank of Hong Kong.