The index closed 18.25 points lower after dropping 19.77 points in the previous session.
Trading on the Ho Chi Minh Stock Exchange increased by 60% to VND21.855 trillion ($889.48 million).
The VN-30 basket, comprising the 30 largest capped stocks, saw 25 tickers fell.
MSN of conglomerate Masan Group dropped 3.8%, followed by MWG of electronics retail chain Mobile World, down 3.5%.
HPG of steelmaker Hoa Phat Group fell 3.2% and BID of state-owned lender BIDV closed 3.1% lower.
VJC of budget airline Vietjet went up 1.9% and SSI of leading brokerage SSI Securities Corporation closed 0.3% higher.
Foreign investors were net buyers to the tune of VND555 billion, mainly buying STB of Ho Chi Minh City-based lender Sacombank and PVD of PetroVietnam Drilling & Well Services Corporation.
The HNX-Index for stocks on the Hanoi Stock Exchange, home to mid and small caps, fell 1.27% while the UPCoM-Index for the Unlisted Public Companies Market dropped 0.81%.