Deripaska and the biggest companies in his empire were included on a U.S. Treasury Department sanctions blacklist in April. Washington said he and fellow tycoons were profiting from association with a Kremlin conducting “malign activities” around the globe.

The sanctions paralyzed Rusal’s supply chain, scared off many customers, froze Deripaska out of Western debt markets and sent shares in his major companies plummeting.

In an illustration of the damage dealt by the sanctions, Russia’s VTB bank said it had become owner of a 9.6 percent stake in En+ after the firm’s stocks sank.

The price slump triggered a margin call, forcing a minority shareholder, Singapore’s AnAn Group, to relinquish the stake to the lender, a VTB executive said.

In a statement issued in Hong Kong, where it is listed, Rusal said Deripaska, a non-executive director of the company, had stepped down as director.

That came a day after the chief executive and seven board members quit, also in a move to distance the firm from Deripaska and his associates.

Deripaska is seeking to persuade Washington to ease the sanctions on his businesses in exchange for him scaling back his association with his companies.

The key element now is for him to reduce his controlling stake. One source familiar with the discussions said Deripaska had been intent on holding on to control, but has now accepted there is no alternative if his businesses are to survive.

The maneuver under consideration, according to three sources familiar with the discussions, would mirror steps taken by another sanctioned Russian tycoon, Viktor Vekselberg.

His Swiss-based company Sulzer bought some of Vekselberg’s shares, prompting the U.S. Treasury Department to say that Sulzer was not at risk from sanctions.

Deripaska currently holds a 66 percent stake in En+. The group declined immediate comment when contacted by Reuters.

The three sources, who asked not to be named, said that the share buyback maneuver was one of several options under consideration for reducing Deripaska’s stake.