The Foreign Institutional Investors (FIIs) were net buyers to the tune of Rs 791.77 crore in the futures & option segment on Monday.According to data released by the NSE, FIIs were net buyers of index futures to the tune of Rs 716.01 crore and bought index options worth Rs 196.71 crore. They were net sellers of stock futures to the tune of Rs 114.75 crore and sold stock options worth Rs 6.20 crore.As per data available on the Sebi website - FIIs were net sellers of stocks worth Rs 336.20 crore in the cash market on Friday. Mutual funds were net buyers of shares worth Rs 314.80 crore on the same day.