Shares fall for fifth straight session as large-cap stocks continued to suffer from an increase in investor selling pressure.
The VN-Index on the Ho Chi Minh Stock Exchange edged down 0.65 per cent to end morning trading at 912.29 points.
On Thursday, December 20, it dropped 0.11 per cent to end at 918.24 points.
On the Ha Noi Stock Exchange, the HNX-Index fell 0.44 per cent to 104.07 points.
The index inched up 0.35 per cent to 104.53 points on Thursday.
According to a report on VNS, more than 119 million shares worth a combined VNĐ2.6 trillion (US$111 million) were traded on the two markets.
The VN30 Index, which tracks the 30 largest stocks by market capitalisation, was down 0.60 per cent to 871.78 points.
Oil prices decreased 5 per cent on Thursday, hitting their lowest level in more than a year, affecting the domestic oil stock group.
Brent crude futures fell 5.05 per cent to settle at $54.35 a barrel. U.S. West Texas Intermediate (WTI) crude futures fell $2.29, or 4.75 per cent, to settle at $45.88 a barrel.
Oil firms that saw their stock prices fall were PetroVietnam Drilling & Well Services Corporation (PVD), PetroVietnam Technical Services Corporation (PVS), PetroViet Nam Coating JSC (PVB), Viet Nam National Petroleum Group (PLX) and PetroVietnam Gas JSC (GAS), with falling by between 1.6 and 4.5 per cent.
Other large-caps were also hit, including steel maker Hoà Phát Group (HPG), dairy firm Vinamilk (VNM), Vincom Retail (VRE) and Techcombank (TCB).