The foreign institutional investors (FIIs) were net sellers to the tune of Rs 317.63 crore in the futures & option segment on Tuesday.According to data released on the NSE website, FIIs were net buyers of index futures to the tune of Rs 79.81 crore, and they bought index options worth Rs 107.26 crore. They were net sellers of stock futures to the tune of Rs 493.91 crore and they sold stock options worth Rs 10.80 crore.As per data available on the Sebi website - FIIs were net buyers of stocks worth Rs 81.50 crore in the spot market on the Monday. Domestic mutual funds (MFs) sold shares worth Rs 169.54 crore on the same day.