HANOI, July 30 (Xinhua) -- Vietnam's central bank on Monday adjusted up its reference exchange rate between Vietnamese dong and U.S. dollar by 10 Vietnamese dong to 22,659 Vietnamese dong per U.S. dollar.

With the current trading band of plus or minus 3 percent, the ceiling exchange rate is 23,339 Vietnamese dong per U.S. dollar and the floor rate is 21,979 Vietnamese dong per U.S. dollar, said the State Bank of Vietnam.

Meanwhile, listed rates at big commercial banks in Vietnam advanced significantly against last Friday. BIDV raised the buying rate by 30 Vietnamese dong to 23,200 Vietnamese dong per U.S. dollar and the selling rate by 40 Vietnamese dong to 23,280 Vietnamese dong per U.S. dollar.

Both rates at Vietcombank went up by 35 Vietnamese dong to 23,175 Vietnamese dong per U.S. dollar for buying and 23,290 Vietnamese dong for selling.

Last week, the reference exchange rates saw one up and two downs with total magnitude of 10 Vietnamese dong and 21 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.