The Foreign Institutional Investors (FIIs) were net sellers to the tune of Rs 138.69 crore in the futures & option segment on Monday.According to data released by the NSE, FIIs were net sellers of index futures to the tune of Rs 70.72 crore while bought index options worth Rs 3.35 crore. They were net sellers of stock futures to the tune of Rs 87.29 crore while bought stock options worth Rs 15.97 crore.As per data available on the Sebi website - FIIs were net buyers of stocks worth Rs 478.10 crore in the cash market on Friday. Mutual funds were net buyers of shares worth Rs 129.87 crore on the same day.