The arrangement was made after Vekselberg was placed under sanctions in a crackdown by the United States on President Vladimir Putin's inner circle as retaliation for alleged Russian interference in the 2016 U.S. election.

Vekselberg has reduced his stake in engineering firm Oerlikon to 19.9 percent, a spokesman for the billionaire's Renova Holding said, down from 43 percent previously held by various entities connected to him.

His stake in steelmaker Schmolz + Bichenbach has dropped to 12.6 percent from 42 percent.

The reduction comes after minority shareholders Evgeny Olkhovik and Vladimir Kremer increased their stake in Liwet Holding, the Swiss investment vehicle of Vekselberg's Renova Holding, used to invest in the Swiss companies.

Renova managers meanwhile have exercised their options to shares in Liwet, meaning they also get stakes in Oerlikon and Schmolz + Bichenbach, a statement from Liwet said.

OC Oerlikon has said it has not directly been affected by the U.S. sanctions but has said some financial institutions still required explanations over the sanctions on Vekselberg.

"We note the publication regarding the change in the shareholding structure within Liwet Holding and are examining its content," a spokesman for Oerlikon said.

Schmolz + Bichenbach could not be immediately reached for comment.

(Reporting by John Revill and Oliver Hirt; Editing by Alexander Smith)

By John Revill and Oliver Hirt