It has risen 8.55% since the beginning of this year.
Techcombank sold the dollar VND2 higher at VND24,877, while Eximbank kept the rate unchanged at VND24,875.
The State Bank of Vietnam raised its reference rate up 0.008% to VND23,695.
The USD Index, which measures its strength against major currencies, went up 0.31% to 111.18 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.