The major Swiss bank UBS manages billions in assets for rich Russians.

Russians, who may be affected by measures to punish Moscow's attack on Ukraine, account for 0.7 percent of the $3.145 trillion in assets under management in the Wealth Management division, according to UBS's annual report released on Tuesday.

This corresponds to around 22 billion dollars.

This is the first time that UBS has presented information on the assets under management in the Russian business.

Rival Credit Suisse had put the proportion of assets managed by Russians at around four percent of the total volume in mid-March.

According to the quarterly report, the withdrawal from markets and sanctions related to Russia's invasion of Ukraine led to a decline in assets in the wealth management division.

UBS Chief Financial Officer Kirt Gardner said in a conference call that there had been "some outflows...(in business) with Russian clients as a result of the sanctions."

When asked if the bank had frozen assets related to the sanctions imposed on Russian individuals and entities, CEO Ralph Hamers said: "Many banks have ... sanctioned parties on their books and we have some too, but we give those numbers not known."

UBS's direct involvement in Russia fell to $0.4 billion by the end of March from $0.6 billion at the end of 2021. Across all business areas, the Russia business caused a loss of around $100 million in the first quarter.