The index closed 0.87 points lower after gaining 2.84 points on Thursday.
Trading on the Ho Chi Minh Stock Exchange (HoSE) fell by 6.97% to VND10.89 trillion ($463.80 million).
Foreign investors were net sellers to the tune of VND332.06 billion, mainly selling VHM of property giant Vinhomes and VND of brokerage VNDirect.
The VN-30 basket, comprising the 30 largest capped stocks, saw 12 tickers fall.
NVL of property developer Novaland Group lost 1.9%, followed by SAB of brewer Sabeco with a 1.6%.
VCB of state-owned lender Vietcombank closed 1.3% lower and BVH of insurance company Bao Viet Holdings lost 1.2%.
GVR of Vietnam Rubber Group gained 2.7% and POW of electricity producer Petrovietnam Power Corporation went up 1.1%.
The HNX-Index at the Hanoi Stock Exchange, where mid and small caps list, was up 0.40% while the UPCoM-Index at the Unlisted Public Companies Market was down by 0.16%.