Vietcombank sold the dollar at VND24,820, up 0.08% from the previous day.
Meanwhile, the greenback is sold at VND25,550 on the black market, down 0.20%.
The State Bank of Vietnam (SBV) raised its reference rate by 0.01% to VND23,957.
From the year to date, the dollar has increased against the dong by 1.64%.
Globally, the U.S. dollar held steady against a handful of rival currencies on Wednesday, as traders weighed what impact hotter-than-expected inflation data could have on chances of an interest rate cut at the Federal Reserve's June meeting.
The dollar index, which measures the greenback against a basket of peer currencies, was little changed at 102.91.
Against the yen, the dollar eased 0.15% to 147.43, giving the Japanese currency some relief after it saw its biggest fall in a month on Tuesday following Bank of Japan Governor Kazuo Ueda's slightly bleaker assessment of the nation's economy.
The euro was mostly flat at $1.0925, and so was sterling at $1.2793.