The dollar has surged in the wake of the U.K. vote to exit the European Union (EU) as investors sought assets perceived to be safe, but there might not be too much demand left from nervous buyers.
Adrian Zuercher, UBS' head of asset allocation for Asia, said the volatility may have run its course.
"At the moment, the U.S. dollar is supported by this risk off sentiment, but we also think there's a limit to that," he told CNBC's "Squawk Box."
"The next one to two weeks are definitely supportive for the U.S. dollar, but afterwards, it'll start to peter out."
The greenback has certainly rallied in the wake of Friday's release of referendum results that surprised markets by showing the U.K. voted to exit the EU, an outcome labelled Brexit, and the political chaos it sparked as Prime Minister David Cameron stepped down, leaving the government there essentially rudderless.
The U.S. dollar index, which measures the greenback against a basket of currencies, touching levels as high as 96.705 on Monday, up from levels of as low as 93.019 last week before the referendum results. At 12:38 p.m. SIN/HK, the dollar index was at 96.042.
But the rally may not last much longer, Zeurcher said.
"We think at one point, risk appetite will come back. We will see more coordinated central bank action and probably more fiscal action from the governments and therefore risk appetite should rebound," he said, noting that this was why he didn't think a safe-haven play on gold offered much benefit at this stage.
Zeurcher pointed to another reason the dollar's rally may not last much longer: Post-Brexit market volatility has likely pushed back the timing of U.S. Federal Reserve's next interest rate hike, he said.
"The Fed has basically postponed its rate hikes, we think, until December so that's a bit less support for the U.S. dollar," Zuercher said, noting that UBS now expects just one interest rate hike this year, down from a previous expectation for two.