The Foreign Institutional Investors (FIIs) were net sellers to the tune of Rs 158.71 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 77.71 crore and sold index options worth Rs 15.14 crore. They were net sellers of stock futures to the tune of Rs 63.18 crore and sold stock options worth Rs 2.68 crore.As per data available on the Sebi website - FIIs were net buyers of stocks worth Rs 96.70 crore in the cash market on Monday. Mutual funds were net buyers of shares worth Rs 649.80 crore on the same day.