Vietcombank sold the dollar at VND25,420, down 0.12% from Tuesday. The greenback declined by roughly the same rate to VND25,600 on the black market.
The State Bank of Vietnam lowered its reference rate by 0.02% to VND24,332.
Globally, the dollar drifted slightly lower on Wednesday in indecisive trading as a lack of clarity on President Donald Trump's plans for tariffs kept financial markets guessing, Reuters reported.
A lack of specific plans from Trump's first day in office saw the dollar start the week with a 1.2% slide against a basket of major peers. It stabilized on Tuesday, ending flat after an attempted rebound fizzled, with U.S. officials saying any new taxes would be imposed in a measured way.
The dollar index, which tracks the currency against the euro, yen and four other top rivals, was down 0.14% at 108. The euro slipped 0.07% to $1.0420, while the yen edged up slightly to 155.40 per dollar.
"While Trump threatened tariffs up to 25% on Mexico and Canada, he refrained from enacting them despite signing several executive orders," said Tony Sycamore, an analyst at IG.
"His decision not to target China is being taken as a possible sign of a more cautious approach to tariffs than promised during his campaign, reducing inflation risks and potential hawkish Federal Reserve actions."