The Foreign Institutional Investors (FIIs) were net buyers to the tune of Rs 251.32 crore in the futures & option segment on Tuesday.According to data released by the NSE, FIIs were net sellers of index futures to the tune of Rs 159.28 crore while they bought index options worth Rs 127.77 crore. They were net sellers of stock futures to the tune of Rs 218.14 crore and sold stock options worth Rs 1.66 crore.As per data available on the Sebi website - FIIs were net buyers of stocks worth Rs 794.70 crore in the cash market on Monday. Mutual funds were net buyers of shares worth Rs 65.58 crore on the same day.