HANOI, July 12 (Xinhua) -- Vietnam's central bank on Thursday adjusted up its reference exchange rate between Vietnamese dong and U.S. dollar by 5 Vietnamese dong to 22,652 Vietnamese dong per U.S. dollar.

With the current trading band of plus or minus 3 percent, the ceiling exchange rate is 23,332 Vietnamese dong per U.S. dollar, and the floor rate is 21,972 Vietnamese dong per U.S. dollar, said the State Bank of Vietnam.

Meanwhile, listed rates at big commercial banks in Vietnam remained unchanged from Wednesday. Both Vietcombank and BIDV maintained the rates at 23,005 Vietnamese dong per U.S. dollar for buying and 23,075 Vietnamese dong per U.S. dollar for selling.

This week, the reference exchange rates has seen three ups and one down with total magnitude of 20 Vietnamese dong and 6 Vietnamese dong, respectively.

According to the central bank, as of June 11, the reference exchange rate rose 0.63 percent against the end of 2017, while the average rate offered by commercial banks advanced 0.47 percent.