The index closed 8.1 points lower after gaining 1.9 points in the previous session.
Trading on the Ho Chi Minh Stock Exchange increased by 12% to VND24.49 trillion (US$960 million).
The VN-30 basket, comprising the 30 largest capped stocks, saw 19 tickers fell.
VIC of private conglomerate Vingroup led with a 6.9% surge, followed by VRE of retail real estate arm Vincom Retail, up 2.7%.
MSN of conglomerate Masan Group gained 2.5% and VHM of property giant Vinhomes closed 1.8% higher.
Nineteen blue chips fell. PLX of fuel distributor Petrolimex dropped 2.8%, and BCM of Becamex Investment and Industrial Development declined by 2.2%.
Foreign investors were net buyers to the tune of VND152 billion, mainly buying VIC of private conglomerate Vingroup and SSI of brokerage SSI Securities Corporation.
The HNX-Index for stocks on the Hanoi Stock Exchange, home to mid and small caps, fell 0.23%, while the UPCoM-Index for the Unlisted Public Companies Market went down 0.29%.