UBS suffered a $785m loss in the third quarter of 2023, largely due to the integration of Credit Suisse within the group.
The group said its first quarterly loss in nearly six years was "driven by integration-related expenses", which swelled to $2bn throughout the quarter.
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Integration-related expenses made up $431m of the firm's $4.8bn in operating expenses in Q3, but in some arms of the business the proportion was much higher. 17.3% ($125m) of the group's asset management operating expenses came from integrating Credit Suisse.
In its asset management arm, net new money declined by $1.5bn, and by $8.3bn excluding money market flows and associates, while invested assets declined 3% to $1.6trn.
However, the firm saw $22bn of net new money into its wealth management business, with Credit Suisse Wealth Management gaining net new money for the first time since the beginning of 2022.
This was the second highest third quarter result in over a decade for its wealth management arm, it reported.
In its previous quarterly results, the bank reported its biggest-ever quarterly profit of $29.2bn.
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"We are executing on the integration of Credit Suisse at pace and have delivered underlying profitability for the group in the first full quarter since the acquisition," said group chief executive Sergio Ermotti.
"Our clients have continued to place their trust and confidence in us, contributing to strong inflows across wealth management and our Swiss franchise.
"We are optimistic about our future as we build an even stronger and safer version of the UBS that was called upon to stabilise the financial system in March and one that all of our key stakeholders can be proud of."
