Barclays and UBS face questions over Roman Abramovich’s billion-dollar trusts

Exclusive: Leak shows oligarch was a major client of Barclays in Monaco and UBS in Zurich, with at least $940m in assets held at the banks

Barclays and UBS are facing questions about their ties to Roman Abramovich after his secretive offshore trusts were reorganised shortly before Europe and the UK imposed sanctions on the Russian oligarch.

The Oligarch files, a cache of leaked documents seen by the Guardian, suggest that before Russia invaded Ukraine the two banks held at least $940m (760m) of assets on behalf of Abramovich's trusts and companies he ultimately owned.