On the Ho Chi Minh Stock Exchange, the VN-Index lost 1.16 percent, to close Thursday at 1,036.28 points.
The index had risen 1.58 percent, to close Wednesday at 1,048.42 points.
Liquidity hit a 7-month high with more than 1.34 billion shares worth VND21.8 trillion (US$888 million) traded in the southern market.
The market breadth was positive with gainers outnumbering losers by 281-166. Another 75 closed flat.
Blue chips led the market downtrend. Nineteen out of the top 30 shares by market value and liquidity on the HoSE lost value and only nine gained.
The VN-30 Index, tracking the 30 biggest stocks on HoSE, declined 0.63 percent to close at 1,042.64 points.
In the VN-30 basket, Property giant Vinhomes (VHM), steelmaker Hoa Phat Group (HPG), insurer Bao Viet Holdings (BVH), Vietinbank (CTG), Khang Dien House (KDH), Masan Group (MSN), Mobile World Group (MWG), PV Power (POW), Sabeco (SAB), SSI Securities Inc (SSI), Tien Phong Bank (TPB), Vingroup (VIC), Vincom Retail (VRE) and Vietcombank (VCB) were among the worst performers.
In the banking group, all stocks lost ground, pressured by strong selling force, with losers including Military Bank (MBB), Techcombank (TCB), Vietcombank (VCB), Bank for Investment and Development of Vietnam (BID), VietinBank (CTG), Vietnam International Commercial JS Bank (VIB) and Saigon-Hanoi Commercial JS Bank (SHB), and Tiên Phong Bank (TPB).
Securities stocks decreased towards the end of the session. VN-Index's loss was significantly broadened as securities stocks declined strongly, such as VNDirect Securities Corporation (VND), Saigon-Hanoi Securities JSC (SHS), Viet Capital Incorporation (VCI), Agribank Securities Corporation (AGR) and APG Securities Joint Stock Company (APG).
Energy stocks also performed negatively with losers such as Vietnam National Petroleum Group (PLX), PetroVietnam Technical Services Corporation (PVS), PetroVietnam Drilling and Well Services Corporation (PVD) and Drilling Mud Joint Stock Corporation (PVC).
On the Hanoi Stock Exchange, the HNX-Index rose 1.06 percent to close at 211 points.
Trading value on the northern exchange reached VND1.7 trillion, with trading volume of 136.7 million shares.