Vietcombank sold the dollar at VND24,950 Tuesday, up 0.08% from Monday.
The State Bank of Vietnam lowered its reference rate by 0.09% to VND23,994.
The dollar went up 0.04% to VND25,600 on the black market.
The greenback has increased by 2.17% since the beginning of the year.
Globally the dollar was on the back foot on Tuesday, owing to profit taking and pressured in part by a slightly stronger yen as Japanese government officials continued with their jawboning to defend the currency, Reuters reported.
Against the greenback, the New Zealand dollar rebounded from a four-month low and last bought $0.5999, and likewise for sterling which firmed to $1.2636, away from last week's one-month trough of $1.25755.
The dollar index was last 0.02% lower at 104.20, while the euro rose 0.03% to $1.0840.