The index closed 1.14 points lower after gaining 4.49 points on May 10.
Trading on the Ho Chi Minh Stock Exchange (HoSE) increased by 3.34% to 11.53 trillion VND (491.29 million USD).
The VN-30 basket, comprising the 30 largest capped stocks, saw 16 tickers gain.
Ten blue chips gained, led by NVL of property developer Novaland Group with a 3.8% rise.
The HNX-Index at the Hanoi Stock Exchange, where mid and small caps list, was up 0.24% while the UPCoM-Index at the Unlisted Public Companies Market was up by 0.37%.
