Vietcombank sold the dollar at VND24,590 Wednesday, up 0.08% from Tuesday.
The greenback was sold at VND24,730 on the black market, up 0.73%.
The State Bank of Vietnam increased its reference rate by 0.01% to VND24,065.
It has increased over the dong by 3.62% since the beginning of the year.
Globally, the dollar was largely rangebound on Wednesday, though remained weighed down by dovish Federal Reserve comments, as traders awaited the central bank's policy meeting minutes due later in the day for more clues on its interest rate outlook, according to Reuters.
A slew of Fed officials have signalled in recent days that the U.S. central bank may not need to tighten monetary policy much further than initially thought.
The greenback sat near a two-week low against a basket of currencies on Wednesday and last stood at 105.80.