The Foreign Institutional Investors (FIIs) were net buyers to the tune of Rs 883.55 crore in the futures & option segment on Friday.According to data released by the NSE, FIIs were net sellers of index futures to the tune of Rs 99.29 crore while bought index options worth Rs 608.22 crore. They were net buyers of stock futures to the tune of Rs 383.83 crore while sold stock options worth Rs 9.21 crore.As per data available on the Sebi website - FIIs were net buyers of stocks worth Rs 883.10 crore in the cash market on Thursday. Mutual funds were net buyers of shares worth Rs 111.60 crore on the same day.