HANOI, Oct. 4 (Xinhua) -- Vietnam's central bank on Thursday raised its reference exchange rate between Vietnamese dong and U.S. dollar by 2 Vietnamese dong to 22,720 Vietnamese dong per U.S. dollar.

With the current trading band of plus or minus 3 percent, the ceiling exchange rate is 23,402 Vietnamese dong per U.S. dollar, and the floor rate is 22,038 Vietnamese dong per U.S. dollar, said the State Bank of Vietnam.

Meanwhile, listed rates at big commercial banks in Vietnam went up slightly from Wednesday. Vietcombank raised both rates by 10 Vietnamese dong, buying the greenback at 23,300 Vietnamese dong per U.S. dollar and selling at 23,380 Vietnamese dong per U.S. dollar.

Rates at BIDV advanced by 5 Vietnamese dong to 23,305 Vietnamese dong per dollar for buying and 23,385 Vietnamese dong per dollar for selling.

This week, the reference exchange rates have seen three ups and one down with total magnitude of 7 Vietnamese dong and 1 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.