Vietcombank sold the dollar at VND25,170, up 0.16% from Wednesday.
The State Bank of Vietnam raised its reference rate by 0.04% to VND24,046.
The dollar went up 0.53% to VND25,585 on the black market.
It has increased against the dong by 3.07% since the beginning of the year.
Globally the dollar was firm on Thursday after hotter-than-expected U.S. inflation data squashed lingering expectations of the Fed starting its rate-cutting cycle in June, while the yen languished at the levels last seen in the middle of 1990.
The yen's slide to a 34-year low of 153.24 per U.S. dollar on Wednesday brought intervention fears back as authorities in Tokyo reiterated that they would not rule out any steps to deal with excessive swings.