The market moved sideways for most of the morning but strong selling pressure in the afternoon dragged it down by 20.49 points.
Trading on the Ho Chi Minh Stock Exchange (HoSE) fell by over 4 percent to VND11.33 trillion ($486.9 million).
The VN-30 basket, comprising the 30 largest capped stocks, saw 27 tickers fall.
STB of HCMC-based lender Sacombank dropped 4.9 percent, followed by SSI of leading brokerage SSI Securities, down 4.8 percent.
Other losers included BVH of insurance company Bao Viet Holdings, down 4.5 percent, FPT of IT giant FPT Corp, down 4.2 percent, and BID of second-largest lender BIDV, down 4 percent.
Three blue chips bucked the trend, led by VRE of Vingroup's mall operator arm Vincom Retail and SAB of brewer Sabeco, both gaining 0.4 percent.
VIC of Vietnam's largest conglomerate Vingroup rose 0.1 percent.
Foreign investors were net buyers to the tune of VND3.35 billion, mainly buying VND of brokerage VNDirect Securities, STB and HDB of lender HDBank.
The HNX-Index at the Hanoi Stock Exchange, where mid and small caps list, fell 1.65 percent while the UPCoM-Index at the Unlisted Public Companies Market was down 1.28 percent.