HANOI, June 21 (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 22,622 Vietnamese dong per U.S. dollar.

With the current trading band of plus or minus 3 percent, the ceiling exchange rate is 23,301 Vietnamese dong per U.S. dollar, and the floor rate is 21,943 Vietnamese dong per U.S. dollar, said the State Bank of Vietnam.

Meanwhile, listed rates at big commercial banks in Vietnam advanced slightly against Wednesday. Vietcombank and BIDV raised both rates by 10 Vietnamese dong, buying the greenback at 22,830 Vietnamese dong per U.S. dollar and selling at 22,900 Vietnamese dong per U.S. dollar.

This week, the reference exchanged rates have seen three ups with total magnitude of 26 Vietnamese dong.

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