The dollar rose 0.44% to VND25,030 on Saturday on the black market.
Vietcombank, however, sold the greenback at VND24,840, down 0.05%.
TPBank and Techcombank kept the rate unchanged at VND24,852 and VND24,850, respectively.
The State Bank of Vietnam maintained its reference rate VND23,669, same as Friday.
The dollar has rallied against every major currency this year, boosted by the U.S. Federal Reserve's supersized interest rate hikes as it battles inflation. But recent cooler-than-expected U.S. consumer price data has spurred investor bets that the dollar's rally may be done.
The USD Index, which measures the greenback’s strength against major currencies, rose 0.14% from Friday to 106.05 points.