Foreign institutional investors (FIIs) were net buyers of Rs 808.80 crore on August 17, Thursday according to data released by Sebi today.While FIIs made gross purchases of Rs 1994.60 crore, gross sales totalled Rs 1185.80 crore.Mutual funds (MFs) were net sellers of Rs 23.84 crore on Thursday. MFs made purchases of Rs 448.69 crore and sales of Rs 472.53 crore.