HANOI, May 23 (Xinhua) -- Vietnam's central bank on Wednesday lowered its reference exchange rate between Vietnamese dong and U.S. dollar by 11 Vietnamese dong to 22,584 Vietnamese dong per U.S. dollar.

With the current trade band of plus or minus 3 percent, the ceiling exchange rate is 23,262 Vietnamese dong per U.S. dollar, and the floor rate is 21,906 Vietnamese dong per U.S. dollar, said the State Bank of Vietnam.

On Wednesday, listed rates at big commercial banks in Vietnam dropped slightly. Vietcombank cut both rates by 5 Vietnamese, buying the greenback at 22,735 Vietnamese dong per U.S. dollar and selling at 22,805 Vietnamese dong per U.S. dollar.

Last week, the reference exchanged rates experienced three ups and two downs with total magnitude of 42 Vietnamese dong and 12 Vietnamese dong, respectively.

According to Vietnam's National Financial Supervisory Commission, the central exchange rate in late 2017 rose around 1.6 percent against early 2017, while the average rate offered by commercial banks decreased 0.2 percent, and on the free market dropped some 1.5 percent.