It rose 0.24% from Tuesday to VND25,280 on the black market.
Vietcombank, however, let the dollar slide 0.02% from its historic peak to VND24,882.
ACB lowered the greenback’s value by the same rate to VND24,880, while Techcombank set it at VND24,883.
The State Bank of Vietnam allowed the dong to gain 0.02% in its reference rate of VND23,703.
Trading currency at unofficial exchange points in Vietnam is illegal. As the rate has been rising on the black market, the central bank has ordered banks to review their exchange points and ensure that they follow currency regulations.