The index closed 15.8 points higher after gaining 1.8 points on Tuesday.
Trading on the Ho Chi Minh Stock Exchange (HoSE) increased by 25.8 percent to VND14.17 trillion ($605.04 million), highest since June 21.
The VN-30 basket, comprising the 30 largest capped stocks, saw 28 tickers gain.
TPB of private TPBank rose 4.8 percent to the highest since June 10.
SSI of leading brokerage SSI Securities Corporation gained 3.1 percent, and PNJ of Phu Nhuan Jewelry went up 2.8 percent.
Other gainers included GVR of Vietnam Rubber Group, FPT of IT giant FPT Corporation and BID of state-owned lender BIDV.
VIC of biggest private conglomerate Vingroup was the only blue chip stock that dropped in this session with a 0.9 percent decline.
Foreign investors were net buyers to the tune of VND193.8 billion.
The HNX-Index at the Hanoi Stock Exchange, where mid and small caps list, was up 1.56 percent while the UPCoM-Index at the Unlisted Public Companies Market was up by 1.13 percent.