Vietcombank sold the greenback at VND26,393, a 0.004% dip from Tuesday. The currency rose 0.12% to around VND26,502 on the black market.
The State Bank of Vietnam lowered its reference rate by 0.004% to VND25,137.
Globally, the dollar held gains from Tuesday after Iran said the U.S. had violated a ceasefire, Reuters reported.
The dollar index, which measures the currency against the yen and five other rivals, was little changed at 99.11 on Wednesday after adding 0.15% in the previous session.
The euro gained slightly to $1.1637. The Aussie slipped 0.09% to $0.7160, reversing an earlier gain. New Zealand's dollar jumped 0.6% to $0.5873.
The yen crept up slightly to 159.28 per dollar, but remained close to the 160 level that many market participants view as a red line for intervention to support it.