The Foreign Institutional Investors (FIIs) were net buyers to the tune of Rs 424.68 crore in the futures & options segment on Tuesday.According to data released by the NSE, FIIs were net buyers of index futures to the tune of Rs 94.69 crore and bought index options worth Rs 218.01 crore. They were net buyers of stock futures to the tune of Rs 101.01 crore and bought stock options worth Rs 10.97 crore.