Vietcombank sold the dollar at VND25,470, up 0.04% from Tuesday.
The greenback was steady at VND25,880 on the black market.
The State Bank of Vietnam hiked its reference rate by 0.04% to VND24,258.
The dollar has increased by 4.3% against the dong since the beginning of the year.
Globally, the dollar rallied broadly on Wednesday and bitcoin jumped to an all-time high as investors returned to so-called "Trump trades" with initial results trickling in for an extremely close U.S. presidential election, Reuters reported.
The dollar index - which measures the currency against six major peers including the euro and yen - climbed 1.42% to 104.84.
The euro dropped 1.54% to $1.0760, while the dollar added 1.64% to 154.035 yen.