Heavy sales of blue chips dragged the VN-Index down by 0.23 per cent on Wednesday to a close of 505.40 points.
The HCM City Stock Exchange saw 124 out of 251 listed shares down by the end of the session, including many blue chips, such as Sacombank (STB), down 0.57 per cent, Saigon Securities Inc (SSI), down 0.59 per cent, and Vietcombank (VCB), down 1.28 per cent.
Vinh Son-Song Hinh Hydropower (VSH), the day's most-active share on a volume of 1.75 million, also decline by 0.73 per cent in value.
The overall value of trades on the southern bourse continued being modest at VND1.47 trillion (US$77.3 million), with a volume of 49.6 million shares.
On the Ha Noi Stock Exchange, the HNX-Index fell by 0.74 per cent to end the session at 158.97 points.
The value of trades also eased off by 5 per cent from Tuesday's session to just VND1.3 trillion ($70 million), while volume totalled 48.6 million shares.
Kim Long Securities (KLS) was the most-active share nationwide, with 5 million shares changing hands.
Penny stocks remained central to the day's trading, with a number registering gains, including Lam Dong Pharmaceuticals (LDP), TNG Investment and Trading (TNG) and Can Tho Cement (CCM).
Increased profit-seeking in both large- and small-cap shares caused markets to decline, as investors largely ignored earnings results, said Au Viet Securities Company Deputy Director Le Anh Thi.
A sell-off was inevitable after two or three days of market advances, helping day traders ensure ongoing returns, commented PetroVietnam Securities Company analyst Le Thanh Tung.
No new capital was entering the market, but withdrawals remained modest, which would prevent indices from making a steeper dip, Tung suggested.
Vo Kim Phung, Head of analysis for MHB Securities Company, said that investors remained concerned over the global situation and believed that rallies on international markets stemmed mostly from the publication of first-half corporate earnings, signalling a continuing instability.
Meanwhile, domestic companies listing additional shares were adding to the market imbalance between supply and demand, Phung said.
He said it would be a good sign if the VN-Index could even reach the current resistance mark of 515 points.