Four bankers were found guilty of failing to exercise due diligence after allowing a friend of Vladimir Putin to deposit large sums in Swiss banks.
Former executives at Russia’s Gazprombank’s Zurich branch were fined heavily for assisting musician Sergei Roldugin, dubbed “Putin’s wallet.”
Mr Roldugin allegedly paid in around $30 million (£24 million) between 2014 and 2016.
He provided no convincing explanation for where the money came from.
Banks in Switzerland are required by law to reject or close accounts if they have concerns about the account holder or the source of the funds. The cellist Mr Roldugin is the godfather of President Putin’s eldest daughter, Maria.
The Russian president also bestowed upon him the Order of Alexander Nevsky, a Russian Federation merit award.
Three of the bankers convicted are Russian, and one is Swiss. They were fined 741,000 Swiss francs (£655,600) in total, suspended for two years.
The men, who cannot be identified due to Swiss reporting restrictions, have stated that they will appeal the Swiss court’s decision.
The Zurich court was unable to prove the four had reservations when the Russian musician appeared with millions of dollars. However, the verdict states that they should have acted but did not.
It serves as a warning to bankers across the country that due diligence laws will be strictly enforced.