The index closed 0.79 points lower after gaining 0.83 points in the previous session.
Trading on the Ho Chi Minh Stock Exchange decreased by 8% to VND22.24 trillion ($875 million).
The VN-30 basket, comprising the 30 largest capped stocks, saw 10 tickers fell.
VNM of dairy giant Vinamilk lost 1.9% and BVH of insurance company Bao Viet Holdings closed 1.6% lower.
POW of electricity producer Petrovietnam Power Corporation declined by 1.5% and VIC of private conglomerate Vingroup dropped 1.1%.
Twelve blue chips ended in the green.
STB of Ho Chi Minh City-based lender Sacombank gained 3.7% and SHB of Saigon Hanoi Commercial Bank rose 2.6%.
Foreign investors were net sellers to the tune of VND743 billion, mainly selling MWG of electronics retail chain Mobile World and FPT of IT giant FPT Corporation.
The HNX-Index for stocks on the Hanoi Stock Exchange, home to mid and small caps, fell 0.13%, while the UPCoM-Index for the Unlisted Public Companies Market went up 0.88%.