Who they are
FIIs (now called FPIs) are foreign funds investing in Indian shares. DIIs are Indian institutions: mutual funds, insurance companies, banks and pension funds.
The daily numbers
After the close, NSE publishes how much each group bought and sold in the cash market, in rupees crore. Net = buy minus sell. A negative FII net means foreign funds sold more than they bought that day.
Why streaks matter
One day of selling is noise. Ten days in a row is a trend. That is why our page shows streaks, weekly and monthly totals, and a heatmap instead of only today's number.
Provisional vs final
NSE numbers are provisional, out the same evening. NSDL publishes confirmed FPI figures a day later; they differ a little because they include primary market deals and settle trades properly.
F&O positioning
In futures, what matters is how many contracts each group holds long versus short. If FIIs hold only 20% of their index futures long, they are positioned for a fall.