The index closed 12.21 points lower after gaining 0.46 points in the previous session.
Trading on the Ho Chi Minh Stock Exchange decreased by 6% to VND20.768 trillion ($854 million).
The VN-30 basket, comprising the 30 largest capped stocks, saw 27 tickers fell.
Foreign investors were net seller to the tune of VND234 billion, mainly selling MBB of lender MB and VHM of property giant Vinhomes.
The HNX-Index for stocks on the Hanoi Stock Exchange, home to mid and small caps, fell 0.69%, while the UPCoM-Index for the Unlisted Public Companies Market went down 0.22%.
