Vietcombank sold the dollar at VND24,920, up 0.04% from Tuesday.
The State Bank of Vietnam (SBV) kept its reference rate unchanged at VND23,999.
The dollar went up 0.12% to VND25,580 on the black market.
It has increased against the dong by 2.05% since the beginning of the year.
Globally, the yen languished near a four-month low against the U.S. dollar and a 16-year trough against the euro on Wednesday as traders wagered Japan's monetary settings will remain accommodative even as the central bank ends its negative interest rate policy, Reuters reported.
On Wednesday, the yen weakened to a four-month low of 151.34 per dollar and was last off 0.26% at 151.23, with the multi-decade low of 151.94 within sight and the threat of intervention by Japanese authorities resurfacing.
The dollar index, which measures the U.S. currency against six rivals, rose to 0.019% to 103.87. The euro was steady at $1.08695.