The index closed 0.70 points lower after dropping 6.34 points in the previous session.
Trading on the Ho Chi Minh Stock Exchange decreased by 16% to VND19.67 trillion (US$770 million).
The VN-30 basket, comprising the 30 largest capped stocks, saw 15 tickers fell.
TPB of private TPBank dropped 5.3%, followed by VJC of budget airline Vietjet with a 1.6% fall.
BCM of Becamex Investment and Industrial Development declined by 1.5% and LPB of Fortune Vietnam Bank closed 1.1% lower.
Twelve blue chips gained, led by MBB of lender MB with a 1.7% increase.
Foreign investors were net sellers to the tune of VND1.4 trillion.
They mainly net sold FPT of tech giant FPT Corporation and TPB.
The HNX-Index for stocks on the Hanoi Stock Exchange, home to mid and small caps, rose 0.20%, while the UPCoM-Index for the Unlisted Public Companies Market went down 0.20%.