The Foreign Institutional Investors (FIIs) were net buyers to the tune of Rs 492.15 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 412.03 crore and bought index options worth Rs 64.71 crore. They were net buyers of stock futures to the tune of Rs 8.74 crore and bought stock options worth Rs 6.66 crore.As per data available on the Sebi website - FIIs were net buyers of stocks worth Rs 1,275 crore in the cash market on Thursday. Mutual funds were net buyers of shares worth Rs 193.30 crore on the same day.