The index closed 20.22 points lower after dropping 0.48 points in the previous session.
Trading on the Ho Chi Minh Stock Exchange increased by 57% to VND43.129 trillion (US$1.74 billion).
The VN-30 basket, comprising the 30 largest capped stocks, saw 28 tickers fell.
GVR of Vietnam Rubber Group slid 5.9% while BCM of Becamex Investment and Industrial Development declined by 4.3% and CTG of state-owned lender VietinBank fell 4.2%
Two blue chips gained. VRE of retail real estate arm Vincom Retail went up 7.0% and VIC of private conglomerate Vingroup rose 3.8%
Foreign investors were net seller to the tune of VND945 billion, mainly selling FUEVFVND of exchange-traded fund DCVFMVN DIAMOND and DGC of chemical manufacturer Ducgiang Chemicals Group.
The HNX-Index for stocks on the Hanoi Stock Exchange, home to mid and small caps, fell 1.19%, while the UPCoM-Index for the Unlisted Public Companies Market went down 1.10%.