The index closed 10.23 points lower after dropping 0.44 points in the previous session.
Trading on the Ho Chi Minh Stock Exchange increased by 17% to VND28.049 trillion (US$1.1 billion).
The VN-30 basket, comprising the 30 largest capped stocks, saw 24 tickers fell.
VJC of budget airline Vietjet slid 3.0%, while VPB of private lender VPBank closed 2.7% lower.
MSN of conglomerate Masan Group went down 2.5% and VIC of private conglomerate Vingroup decreased by 2.1%.
Five blue chips gained. FPT of IT giant FPT Corporation saw the biggest growth of 1.5%, followed by MWG of electronics retail chain Mobile World with a 0.8% increase and PLX of fuel distributor Petrolimex, up 0.5%.
Foreign investors were net seller to the tune of VND857 billion, mainly selling HPG of steelmaker Hoa Phat Group and VHM of property giant Vinhomes.
The HNX-Index for stocks on the Hanoi Stock Exchange, home to mid and small caps, rose 0.76%, while the UPCoM-Index for the Unlisted Public Companies Market went up 0.24%.