The State Bank of Vietnam set the daily reference exchange rate at 23,154 VND per USD on May 20, up 3 VND from the previous day (Photo: VNA) Hanoi (VNA) – The State Bank of Vietnam set the daily reference exchange rate at 23,154 VND per USD on May 20, up 3 VND from the previous day. With the current trading band of +/-3 percent, the ceiling rate applied to commercial banks during the day is 23,848 VND/USD and the floor rate 22,459 The rates listed at commercial banks saw fluctuations. At 8:25 am, Vietcombank listed the buying rate at 22,910 VND/USD and the selling rate 23,140 VND/USD, both down 10 VND compared to May 19.