"I see clients being happy with their asset allocation at this stage, they believe the underlying fundamentals are still ok, so they don't trade in or out," Ermotti told CNBC shortly after the bank reported fourth quarter earnings earlier on Tuesday.
"We are in a long term business, we cannot manage our business on a quarter by quarter basis," he said.
Investors will be closely watching results from Swiss rival Credit Suisse, which reports full-year earnings on Thursday, with the wealth management division likely to come under similar scrutiny.
Data from the institute of international finance estimated that EMs saw net non-resident portfolio outflows of $3.6 billion in January, marking an "unprecedented" seventh consecutive month of outflows.
"Renewed concerns about China's growth outlook seem to have fueled a period of elevated global risk aversion that has weighed on portfolio flows to EMs," said chief economist at the group, Robin Koepke.
UBS's Wealth Management Americas unit, bucked the trend, reporting net new money of $16.8 billion in the quarter, as the bank upped their presence in the region.
This mirrored the IIF data, Koepke said, as all EM regions except Latin America were estimated to have faced outflows in January for the third consecutive month, with Latin America seeing $4.2 billion of inflows in January.