Vietcombank sold the dollar at VND25,457, down 0.04% to VND25,457.
The State Bank of Vietnam lowered its reference rate by 0.04% to VND24,245.
The dollar gained 0.02% to VND25,785 on the black market.
It has risen 4.16% against the Vietnamese dong since the beginning of the year.
Globally Asian currencies were firm on Thursday against a dollar knocked by softer-than-expected U.S. inflation, save for the yen which remained squeezed ahead of a Bank of Japan meeting and as U.S. policymakers signaled rates would be kept high for a while yet, Reuters reported.
Overnight the euro went up 0.6% and punched above its 200-day moving average, last buying $1.0811.
The Aussie dollar rose 0.9% to $0.6662 and the New Zealand dollar jumped to a five-month high above $0.62 before settling at $0.6183. The yen climbed, but only by about 0.2%.