It closed 19.7 points lower after losing 13.4 points Thursday.
Trading on the Ho Chi Minh Stock Exchange (HoSE), surged 40% to VND32.33 trillion ($1.33 million).
The VN30 basket, comprising the 30 largest capped stocks, saw 26 tickers fell.
SSI of leading brokerage SSI Securities Corporation posted the biggest plunge at 6.2%, followed by GVR of Vietnam Rubber Group with a 5.8% fall.
VHM of property giant Vinhomes dropped 4.4% and MSN of conglomerate Masan Group closed 4.3% lower.
Four blue chips gained, led by VCB of state-owned lender Vietcombank with a 2.6% rise.
Foreign investors were net sellers for the fifth straight session to the tune of VND180 billion, mainly selling VIC and MSN.
The HNX-Index for stocks on the Hanoi Stock Exchange, home to mid and small caps, dropped 3.46% while the UPCoM-Index for the Unlisted Public Companies Market fell 1.76%.