On the Ho Chi Minh City Stock Exchange, the VN-Index lost 0.6 percent and slipped to 505.62 points.
The trading value also dropped 13.8 per cent from December 23 sessionto 1.25 billion VND (58,900 USD), with 91.4 million shares changinghands.
Most of the 30 blue chips tracked by the VN30Index retreated, pulling the index 0.55 percent lower to finish at562.85 points.
On the Hanoi Stock Exchange, the benchmark HNX-Index pared earlier gains to slide 0.27 percent to 68.12 points.
Only indices that track mid- and small-cap stocks and the manufacturing sector managed to post gains.
Meanwhile, large-cap stocks dragged the HNX30 Index 0.34 percent lower to 129.47 points.
As 73.8 million shares changed hands, trading value on the boursereached a total of more than 625.4 billion VND (29.5 million USD),jumping 41.6 percent from the previous trading day.
Foreign investors continued to be net buyers on both bourses by a combined margin of 56.1 billion VND (2.6 million USD).
"The short-term decline of the VN-Index has not stopped and themarket, in the absence of supportive information, is not strong enoughto create a sustainable rally," said Bao Viet Securities Co's analystNguyen Xuan Binh.
"We maintain a cautious stance asthere was no compelling reason for the increase in the price of theleading shares over the past week."
In addition, thegains in the HNX-Index over the past two weeks have increased risks asthe index is approaching its medium-term resistance level, he added.
However, according to FPT Securities Co, investorscould buy shares with strong fundamentals with the expectation thatcompanies will deliver positive financial results.-VNA