431 tickers, or 91% of all stocks on the Ho Chi Minh Stock Exchange, was in the red at 11:20 a.m.
The index was losing 43 points after falling 13 points in the last two sessions.
The VN30 basket, comprising the 30 largest capped stocks, saw 29 tickers falling, three of them hitting floor prices.
NVL of real estate developer Novaland Group, MWG of electronics retail chain Mobile World and PDR of Phat Dat Real Estate Development was losing around 7%, the biggest dip allowed on a single day.
Other decliners were KDH of real estate firm Khang Dien House, 6.7%, SSI of leading brokerage SSI Securities Corporation, 6.4%, and ACB of Asia Commercial Bank, 6.3%.
SAB of brewer Sabeco was the only gaining blue at 1.6%.
Foreign investors were net selling VND137 billion, mainly focusing on KBC of industrial real estate developer Kinh Bac City and HDB of HDBank.
The HNX-Index for stocks on the Hanoi Stock Exchange, home to mid and small caps, was losing 3.12% while the UPCoM-Index for the Unlisted Public Companies Market was falling 2.14%.