The foreign institutional investors (FIIs) were net buyers to the tune of Rs 47.38 in the futures & option segment in a special three-hour trading session on Saturday.According to data released on the NSE website, FIIs were net buyers of index futures to the tune of Rs 59.06 crore, while they sold index options worth Rs 14.69 crore. They were net sellers of stock futures to the tune of Rs 2.19 crore while they bought stock options worth Rs 5.19 crore.