In April, the Trump administration hit three companies Deripaska controls with sanctions over Russian interference in the 2016 US elections; EN+, Rusal and JSC EuroSibEnergo. Following the announcement, the Treasury Department delayed their implementation - eventually deciding in December that they would be lifted following an aggressive lobbying campaign by Deripaska's network.

Democratic lawmakers sent Mr. Mnuchin a letter on Tuesday seeking an explanation for why the termination of the sanctions was justified. They expressed concern that Mr. Deripaska still maintained “significant ownership” of En+, the holding company that controls Rusal, while transferring shares to VTB, a sanctioned Russian bank. They also said that the government shutdown was hampering their ability to properly review the decision.

The solution approved by the Treasury Department lifts the sanctions against Mr. Deripaska’s companies in exchange for reducing his stake in EN+ from approximately 70 percent to less than 45 percent, and giving up control of that company and Rusal. -New York Times

Deripaska, who had business dealings with former Trump campaign chairman Paul Manafort, was rumored to be Donald Trump's "back channel" to Russian President Vladimir Putin. The Russian oligarch hit back in September - admitting to "collusion" when he served as an FBI asset during the Obama administration.

Deripaska spent $25 million of his own money to bankroll an FBI-supervised operation to rescue a retired FBI agent - Robert Levinson, who was kidnapped in 2007 while working on a 2007 CIA contract in Iran.

FBI agents courted Deripaska in 2009 in a series of secret hotel meetings in Paris; Vienna; Budapest, Hungary, and Washington. Agents persuaded the aluminum industry magnate to underwrite the mission. The Russian billionaire insisted the operation neither involve nor harm his homeland. -The Hill

The FBI then tried to turn Deripaska into an FBI informant - an effort involving twice-demoted DOJ #4 official Bruce Ohr and Christopher Steele - the author of the largely unverified "Steele Dossier."

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https://www.zerohedge.com/news/2019-01-09/house-democrats-grill-mnuchin-over-dropped-sanctions-russian-oligarch-who-was-once