HANOI, Dec. 24 (Xinhua) -- Vietnam's central bank on Monday increased its reference exchange rate between Vietnamese dong and U.S. dollar by 5 Vietnamese dong to 22,790 Vietnamese dong per U.S. dollar.

With the current trading band of plus or minus 3 percent, the ceiling exchange rate is 23,474 Vietnamese dong per U.S. dollar, and the floor rate is 22,106 Vietnamese dong per U.S. dollar, said the State Bank of Vietnam.

Listed rates at big commercial banks went up slightly or remained unchanged. BIDV listed the buying rate at 23,240 Vietnamese dong per U.S. dollar and the selling rate at 23,350 Vietnamese dong per U.S. dollar, both up 5 Vietnamese dong from last Friday.

Rates at Vietcombank remained flat at 23,240 Vietnamese dong per U.S. dollar for buying and 23,330 Vietnamese dong per U.S. dollar for selling.

Last week, the reference exchange rate saw two ups and one down with total magnitude of 9 Vietnamese dong and 2 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.