The index closed 4.46 points lower after gaining 27.38 points on Monday.
Trading on the Ho Chi Minh Stock Exchange (HoSE) increased by 1.31% to VND11.86 trillion ($500 million).
The VN-30 basket, comprising the 30 largest capped stocks, saw 18 tickers dropped.
VPB of private lender VPBank dropped 2.7%, while BID of state-owned lender BIDV and CTG of state-owned lender VietinBank both dropped 2%.
MBB of lender MB went down 1.6%.
Nine blue chips rose, led by NVL of property developer Novaland Group with a 3.2% rise.
PLX of fuel distributor Petrolimex gained 3% and HDB of HDBank went up 1.1%.
Foreign investors were net sellers to the tune of VND72.15 billion, mainly selling DXG of real estate developer Dat Xanh Group and DPM of Petrovietnam Fertilizer & Chemicals Corporation.
The HNX-Index at the Hanoi Stock Exchange, where mid and small caps list, was down 0.81% while the UPCoM-Index at the Unlisted Public Companies Market was down by 0.82%.