Their top purchases included Duc Giang Chemicals Group (DGC), Sacombank (STB), electrical equipment maker Gelex Group (GEX), conglomerate Masan Group (MSN).
They sold dairy giant Vinamilk, property developer Novaland Group and securities company VNDirect (VND).
They have pulled out nearly VND4 trillion from the market since the beginning of this month, which is set to be the eighth consecutive month of net selling by them.
Domestic retail investors dumped over VND2 trillion worth of securities on the Ho Chi Minh Stock Exchange, ending four weeks of buying.
They sold DGC, VPBank and steelmaker Hoa Phat Group (HPG).
The VN-Index was at 1,484 points Monday morning, down nearly 1 percent since the beginning of the year.