Vietcombank sold the greenback at VND25,467, down 0.008% from Wednesday.
The State Bank of Vietnam lowered its reference rate by the same percentage to VND24,255.
The dollar was steady on the black market at VND25,850.
Globally the British pound held broadly steady on Thursday ahead of a rate decision from the Bank of England (BoE) later in the day, while the dollar was on the back foot as it awaited fresh market catalysts, Reuters reported.
Currencies were trading in tight ranges following a holiday in the United States and as investors looked not only to the BoE but also central bank decisions in Switzerland and Norway.
Sterling last bought $1.2719 after having eked out a slight gain in the previous session, while the euro rose 0.03% to $1.0747.