Vietcombank sold the dollar at VND24,710, down 0.20% from Monday.
The State Bank of Vietnam raised its reference rate by 0.03% to VND24,097.
The greenback rose 0.04% to VND24,640 on the black market.
It has gained over the dong by 4.13% since the beginning of the year.
The U.S. dollar fell against a basket of currencies on Monday, tracking a retreat in U.S. Treasury yields from the 5% level hit earlier in the session, and as traders awaited fresh U.S. economic data due later this week, Reuters reported.
The yield on the benchmark 10-year U.S. Treasury note declined on Monday after briefly rising above 5.0%, hitting the July 2007 milestone that it briefly attempted to scale last week and further threatening an economic slowdown on higher borrowing costs.
The dollar index, which measures the currency's strength against a basket of six rivals, was 0.6% lower at 105.56. The index had risen as high as 106.33 earlier in the session.