Foreign institutional investors (FIIs) were net sellers of Rs 343.60 crore on July 14, Friday according to data released by Sebi today.While FIIs made gross purchases of Rs 911.70 crore, gross sales totalled Rs 1255.30 crore.Mutual funds (MFs) were net sellers of Rs 24.14 crore on Friday. MFs made purchases of Rs 290.41 crore and sales of Rs 314.55 crore.