More recently, he has emerged as a bit player in the special counsel’s investigation into Russian interference in the election and any connection to the Trump campaign.
But the sanctions had roiled the global aluminum market, leading even some sanctions advocates to acknowledge unintended negative effects on companies in the United States, Ireland, Sweden, Jamaica, Guinea and elsewhere.
The solution approved by the Treasury Department would lift the sanctions against Mr. Deripaska’s companies in exchange for him reducing his stake in EN+ from approximately 70 percent to less than 45 percent, and giving up control of that company and Rusal.
Mr. Deripaska would remain on the sanctions list, the department said, casting the agreement as a way to punish the oligarch by separating him from his companies without creating broader economic problems.
Representative Lloyd Doggett, Democrat of Texas, accused the administration of approving “a Rusal ruse” to “cover for one of Putin’s closest buddies.”
Other Democrats contended that the Treasury Department was trying to ram the sanctions-relief decision through before the new Congress had time to stop it, and before the special counsel issued findings that might touch on Mr. Deripaska’s work with Paul Manafort, Mr. Trump’s former campaign chairman and a target of the special counsel investigation.
In a letter sent Friday to Treasury Secretary Steven Mnuchin, Senator Robert Menendez of New Jersey questioned whether Mr. Deripaska’s companies had agreed to the terms. Mr. Menendez, the top Democrat on the Senate Foreign Relations Committee, which is also reviewing the sanctions decision, asked Mr. Mnuchin how the Treasury Department could “ensure that Mr. Deripaska does not retain and exercise informal influence over the decision making and operations of Rusal.”
“Treasury will continue to work closely with Congress as questions arise related to this intended delisting,” a department spokesman said in a statement. The agreement between the department and Mr. Deripaska’s companies “will significantly diminish Deripaska’s ownership and sever his control, while mandating an unprecedented level of transparency for Treasury into the dealings of these companies.”