The Foreign Institutional Investors (FIIs) were net buyers to the tune of Rs 456.75 crore in the futures & option segment on Friday.According to data released by the NSE, FIIs were net buyers of index futures to the tune of Rs 594.60 crore and bought index options worth Rs 0.79 crore. They were net sellers of stock futures to the tune of Rs 149.41 crore while bought stock options worth Rs 10.77 crore.As per data available on the Sebi website - FIIs were net buyers of stocks worth Rs 526.90 crore in the cash market on Thursday. Mutual funds were net sellers of shares worth Rs 71.06 crore on the same day.