DII's and FII's

Foreign institutional investors (FII) are the investment funds investing in a country other than the country in which it is registered. For example investment by US mutual fund Company in UK company shares.
Domestic institutional investors(DII) are the  investors or investment fund invest in the own country where it is registered. For example US mutual fund investing in US companies.
DII's-  domestic institutional investors,FII's -Foreign institutional investors.
Following are the various institutional investors:-

• Hedge funds
• Mutual funds
• Pension funds
• Insurance companies

Institutional investors buys the various securities like equity shares, Debentures etc in companies.