Vietcombank sold the dollar at VND24,610, up 0.14% for the day. On Tuesday it closed at VND24,575, lowest since Jan. 10.
The State Bank of Vietnam lowered its reference rate by 0.13% to VND23,991.
The greenback went up 0.04% to VND25,000 on the black market.
It has risen by 0.78% against the dong since the beginning of the year.
Globally the dollar headed for its biggest monthly gain since September and the yen for its sharpest drop in nearly a year on Wednesday, as traders waited on a U.S. rates decision to round out January, Reuters reported.
The dollar has gained 2% against a basket of major currencies this month as markets dialled back expectations on the speed and scale of rate cuts in the face of strong U.S. economic data and pushback from central bankers.
The dollar was steady at $1.0844 per euro and a touch weaker at 147.23 yen early in the Asia day, with a summary showing discussion of ending negative interest rates at the Bank of Japan's January meeting helping support the yen.