QFII is the acronym of qualified foreign institutional investor. It is a transitional system for a country to introduce foreign capital and open its capital market to a limited extent when the currency is not fully convertible and the capital account is not yet open. This system requires foreign investors to meet certain conditions if they want to enter a country's securities market, remit a certain amount of foreign exchange funds after being approved by the relevant departments of the country, and convert them into local currency to invest in the local securities market through a strictly supervised special account.

QDII is the acronym of qualified domestic institutional investor. It is a securities investment fund established in a country and approved by the relevant departments of that country to engage in securities business such as stocks and bonds in overseas securities markets. Like QFII, it is also a transitional institutional arrangement that allows domestic investors to invest in overseas securities markets to a limited extent when the currency is not fully convertible and the capital account is not yet open.