The index climbed to the 1,280-range in the morning but gradually fell to around 1,270 points in the afternoon before closing with a near 3-point gain.

Trading value on the Ho Chi Minh Stock Exchange (HoSE), on which the index is based, fell 10.5 percent to VND16 trillion. The bourse saw 188 tickers gain and 171 lose.

Foreign investors were net sellers for the third session in a row to the tune of VND1.39 trillion, quadrupling from Tuesday and the highest since June 4.

Strongest pressure was seen in VIC of biggest private conglomerate Vingroup, Vietnam Maritime Commercial Joint Stock Bank (MSB) and CTG of state-owned lender VietinBank.

The VN30 basket, comprising the 30 largest capped stocks, saw 21 tickers in the red, led by HDB of HDBank with a 3.6 percent drop.

It was followed by SSI of leading brokerage SSI Securities Corporation, down 2.3 percent, and GAS of state-owned Petrovietnam Gas, 1.8 percent.

PDR of Phat Dat Real Estate Development lost 1.7 percent, while CTG of state-owned lender VietinBank fell 1.2 percent.

The HNX-Index for stocks on the Hanoi Stock Exchange, home to mid and small caps, fell 0.1 percent, while the UPCoM-Index for the Unlisted Public Companies Market gained 0.73 percent.