The foreign institutional investors (FIIs) were net sellers to the tune of Rs 52.03 crore in the futures & option segment on Monday.According to data released on the NSE website, FIIs were net sellers of index futures to the tune of Rs 323.25 crore while they bought index options worth Rs 29.39 crore. They were net buyers of stock futures to the tune of Rs 262.41 crore and they sold stock options worth Rs 20.58 crore.As per data available on the Sebi website - FIIs were net buyers of stocks worth Rs 508.90 crore in the spot market on Friday. Domestic mutual funds (MFs) were net sellers of shares worth Rs 302.76 crore on the same day.