A Bermuda court said Credit Suisse must pay billionaire Bidzina Ivanishvili about $555m for allowing a private banker to steal from the former Georgia prime minister and mismanage his money.

Ivanishvili sued the bank for breach of contract and fiduciary duty after his private banker, Patrice Lescaudron, admitted to cutting and pasting signatures to make unauthorised stock bets. Credit Suisse had said it too was a victim of Lescaudron and shouldn’t be held liable for his actions.