The index closed 6.74 points higher after gaining 6.32 points on Tuesday.
Trading on the Ho Chi Minh Stock Exchange (HoSE) increased by 28.72% to VND17.52 trillion ($744.96 million).
The VN-30 basket, comprising the 30 largest capped stocks, saw 21 tickers gain.
HPG of steelmaker Hoa Phat Group rose 4%, followed by GVR of Vietnam Rubber Group with a 3.7% increase.
MSN of conglomerate Masan Group and SSI of leading brokerage SSI Securities Corporation closed 1.2% higher.
Seven blue chips fell. VJC of budget airline Vietjet closed 1.2% lower and VHM of property giant Vinhomes lost 0.9%.
Foreign investors were net buyers to the tune of VND37.23 billion, mainly buying HPG of steelmaker Hoa Phat Group.
The HNX-Index at the Hanoi Stock Exchange, where mid and small caps list, was up 1.31% while the UPCoM-Index at the Unlisted Public Companies Market was up by 0.74%.