This was its 11th gaining session in a row, and the dong has depreciated by 7.5% since the beginning of the year.
Eximbank sold the dollar 0.41% higher at VND24,660, while VPBank hiked the rate by 0.12% to VND24,680.
The State Bank of Vietnam (SBV) set the reference rate 0.19% higher at VND23,682.
The U.S. Dollar Index, which measures the greenback’s strength against six major currencies, hovers around the 20-year high level at 110 points.
Vietnam foreign exchange reserves has declined by around 20% so far this year as the central bank sells its dollars to keep the exchange rate stable.