The index closed 0.45 points lower after losing 5.04 points on Wednesday.
Trading on the Ho Chi Minh Stock Exchange (HoSE) fell by 22.56% to VND13.27 trillion ($563.66 million).
The VN-30 basket, comprising the 30 largest capped stocks, saw 15 tickers fall.
SAB of brewer Sabeco lost 1.9%, and POW of electricity producer Petrovietnam Power Corporation closed 1.5% lower.
MSN of conglomerate Masan Group and VNM of dairy giant Vinamilk both fell 1.2%.
Eleven blue chips gained, led by GAS of state-owned Petrovietnam Gas and PDR of Phat Dat Real Estate Development, both increased by 2.1%.
Foreign investors were net buyers to the tune of VND397.78 billion, mainly buying HPG of steelmaker Hoa Phat Group and VND of brokerage VNDirect.
The HNX-Index at the Hanoi Stock Exchange, where mid and small caps list, was up 0.27% while the UPCoM-Index at the Unlisted Public Companies Market was down by 0.32%.