The index closed 7.55 points lower after gaining 7.12 points in the previous session.
Trading on the Ho Chi Minh Stock Exchange decreased by 39% to VND11.81 trillion ($486.76 million).
The VN-30 basket, comprising the 30 largest capped stocks, saw 23 tickers fell.
STB of Ho Chi Minh City-based lender Sacombank fell 3.2%, followed by SSI of leading brokerage SSI Securities Corporation, down 3.1%, and TCB of the largest private lender Techcombank, down 2.5%.
Five blue chips bucked the trend, led by SAB of brewer Sabeco with a 2.1% gain.
Foreign investors were net buyers to the tune of VND41 billion, mainly buying HPG of steelmaker Hoa Phat Group and VPB of private lender VPBank.
The HNX-Index for stocks on the Hanoi Stock Exchange, home to mid and small caps, fell 0.98%, while the UPCoM-Index for the Unlisted Public Companies Market went down 0.64%.