The benchmark VN-Index on the Ho Chi Minh Stock Exchange fell 0.50 per cent to close at 946.68 points.
The southern market index inched up a total 0.53 per cent the previous two days.
More than 52.7 million shares were traded on the southern bourse, worth VND1.27 trillion (US$55 million).
Financial and banking stocks weighed on the market on Thursday morning.
The brokerage, insurance and banking sector indices lost between 0.3 per cent and 1 per cent, data on vietstock.vn showed.
Other sectors that also saw shares struggle included food and beverage, petroleum and mining and utilities.
On the opposite side, technology, healthcare and pharmaceuticals, and seafood processing performed well.
Large-cap stocks VN30-Index fell 0.46 per cent to end at 859.70 points in the morning session.
The modest liquidity and poor performing local stocks were attributed to investors’ caution amid worries about the global economic downturn.
On the Ha Noi Stock Exchange, the HNX-Index dropped 0.72 per cent to end at 102.79 points.
The HNX-Index rose 0.47 per cent on Thursday.
More than nine million shares were traded on the northern bourse, worth VND98 billion.
Afternoon trading starts at 1pm.