The index closed 35.05 points higher after gaining 14.57 points on Tuesday.
Trading on the Ho Chi Minh Stock Exchange increased by nearly 24 percent to VND16.57 trillion ($714 million), the highest of eight sessions.
The VN-30 basket, comprising the 30 largest capped stocks, saw 27 tickers gain.
PNJ of Phu Nhuan Jewelry and FPT of IT giant FPT Corporation hit ceiling prices with a gain of 7 percent and 6.9 percent, respectively.
It was followed by GVR of Vietnam Rubber Group and VPB of private lender VPBank, both up 5 percent.
Two blue chips fell, with HPG of steelmaker Hoa Phat Group losing 1.3 percent and PDR of Phat Dat Real Estate Development falling 0.8 percent.
Foreign investors were net buyers to the tune of VND3.16 billion, focusing on DCM of Petro Vietnam Ca Mau Fertilizer and DPM of Petrovietnam Fertilizer & Chemicals Corporation.
The HNX-Index at the Hanoi Stock Exchange, where mid and small caps list, was up 2.93 percent while the UPCoM-Index at the Unlisted Public Companies Market was up by 1.78 percent.