Sanctioned Russian billionaire banker Mikhail Fridman was locked out of the private-equity firm...

Russian billionaire and banker, Mikhail Fridman, was locked out of the investment firm he cofounded after he was hit by European Union sanctions, the company announced on Wednesday.

London-based LetterOne said in a press release that Fridman and Russian banker Petr Aven had stepped down from the company's board and will no longer have any dealings with the group. Fridman and Aven jointly own under 50% of LetterOne, so the company has avoided sanctions imposed on the two men.

Chairman Mervyn Davies, who has now taken control of LetterOne, told the Financial Times that employees aren't allowed to speak to Fridman. LetterOne, founded in 2013, has also locked Fridman out of its offices and blocked him from having access to documents, Davies told the FT.