HANOI, March 12 (Xinhua) -- Vietnam's central bank on Monday adjusted its reference exchange rate between Vietnamese dong and U.S. dollar up by 5 Vietnamese dong to 22,461 Vietnamese dong per dollar.

With the current trading band of plus or minus 3 percent, the ceiling exchange rate is 23,134 Vietnamese dong per dollar, and the floor rate is 21,790 Vietnamese dong per dollar, said the State Bank of Vietnam.

Major commercial banks in Vietnam, including Vietcombank and BIDV, kept their exchange rates unchanged on Monday morning. Meanwhile, the rates listed at Vietinbank rose by 48 Vietnamese dong to 22,724 Vietnamese dong per dollar (buying) and 22,794 Vietnamese dong per dollar (selling).

The country kept foreign exchange rates fairly stable in 2017. According to Vietnam's National Financial Supervisory Commission, the central exchange rate in late 2017 increased around 1.6 percent against early 2017, while the average rate offered by commercial banks dropped 0.2 percent, and that on the free market declined some 1.5 percent.

Vietnam's foreign reserve has hit an all-time record high of 53 billion U.S. dollars as of Jan. 10, according to the central bank. The reserve rose by nearly 11 billion dollars from mid-2017 and by roughly 12 billion dollars from late last year.