The index closed 9.94 points lower after dropping 12.05 points in the previous session.
Trading on the Ho Chi Minh Stock Exchange increased by 83% to VND34.12 trillion (US$1.31 billion).
The VN-30 basket, comprising the 30 largest capped stocks, saw 10 tickers gained and 20 fell.
GVR of Vietnam Rubber Group plunged 5.9%, followed by BCM of Becamex Investment and Industrial Development with a 5.8% decline.
VIC of private conglomerate Vingroup fell 4.1% and SSI of brokerage SSI Securities Corporation closed 2.8% lower.
Ten blue chips gained. VHM of property giant Vinhomes rose 4.5% and MWG of electronics retail chain Mobile World went up 3.1%.
Foreign investors were net buyers to the tune of VND518 billion, mainly buying HPG of steelmaker Hoa Phat Group and MWG of electronics retail chain Mobile World.
The HNX-Index for stocks on the Hanoi Stock Exchange, home to mid and small caps, fell 1.78%, while the UPCoM-Index for the Unlisted Public Companies Market went down 1.35%.