The index closed 1.2 points lower after losing 9.95 points on Thursday.
Trading on the Ho Chi Minh Stock Exchange (HoSE) fell by 31.71% to VND10.78 trillion ($459.76 million), lowest in seven sessions.
The VN-30 basket, comprising the 30 largest capped stocks, saw 14 tickers dropped.
HPG of steelmaker Hoa Phat Group posts the biggest drop of 1.4%, followed by VCB of state-owned lender Vietcombank with a 1.3% decline.
HDB of HDBank and VHM of property giant Vinhomes both lost 1%.
Twelve blue chips gained, led by SSI of leading brokerage SSI Securities Corporation with a 3% rise.
GVR of Vietnam Rubber Group went up 1.9% and STB of Ho Chi Minh City-based lender Sacombank climbed 1.4% higher.
Foreign investors remained cautious. They net sold VND158.5 billion, mainly in STB and KDH of real estate firm Khang Dien House.
The HNX-Index at the Hanoi Stock Exchange, where mid and small caps list, was up 0.08% while the UPCoM-Index at the Unlisted Public Companies Market was down by 0.23%.