The Foreign Institutional Investors (FIIs) were net buyers to the tune of Rs 1,380.94 crore in the futures & option segment on Friday.According to data released by the NSE, FIIs were net buyers of index futures to the tune of Rs 1,461.37 crore and bought index options worth Rs 337.74 crore. They were net sellers of stock futures to the tune of Rs 416.14 crore and sold stock options worth Rs 2.03 crore.