The foreign institutional investors (FIIs) were net buyers to the tune of Rs 215.69 crore in the futures & option segment on Friday.According to data released on the NSE website, FIIs were net buyers of index futures to the tune of Rs 79.61 crore and they bought index options worth Rs 29.30 crore. They were net buyers of stock futures to the tune of Rs 108.27 crore while they sold stock options worth Rs 1.49 crore.As per data available on the Sebi website - FIIs were net buyers of stocks worth Rs 461.70 crore in the cash market on Thursday. Domestic mutual funds (MFs) were net buyers of shares worth Rs 262.80 crore on the same day.