The U.S. Treasury in April imposed sanctions against billionaire Oleg Deripaska and the eight companies in which he is a large shareholder, including giant aluminium exporter Rusal, in response to what it called "malign activities" by Russia.
Deripaska controls 66 percent of En+, which in turn controls 48 percent of Rusal.
(Reporting by Timothy Ahmann; Editing by Jeffrey Benkoe)