The foreign institutional investors (FIIs) were net sellers to the tune of Rs 57.74 crore in the futures & option segment on Friday.According to data released on the NSE website, FIIs were net buyers of index futures to the tune of Rs 118 crore, and they bought index options worth Rs 128.77 crore. They were net sellers of stock futures to the tune of Rs 304.34 crore and they sold stock options worth Rs 0.18 crore.As per data available on the Sebi website - FIIs were net buyers of stocks worth Rs 322.60 crore in the spot market on the Thursday. Domestic mutual funds (MFs) bought shares worth Rs 105.92 crore on the same day.