The U.S. Department of the Treasury has extended to November 12 the deadline for investors to divest their holdings in Russian companies EN + Group and United Company RusAl, plus six other firms owned by Russian oligarch and billionaire Oleg Deripaska.

Deripaska and his firms were originally sanctioned on April 6. The original deadline for firms to divest from these firms was Oct. 23.

Deripaska's companies hit by the U.S. sanctions are EN +, RusAl, GAZ Group, Agroholding Kuban, Evrosibenergo, Russian Machines Holding, B-Finance, and Basic Element Holdings.

Deripaska is one of the closest friends and confidantes of Russian dictator Vladimir Putin. He's been described as "Putin's favorite industrialist" and is one among 20 wealthy Russians Putin regularly turns to for advice or financial assistance, among other favors.

Last April, the U.S. imposed sanctions on Deripaska and 23 other Russians in response to what it said were "malign activities" by Russia.

In sanctioning Deripaska, the Treasury Department claimed this man "has been accused of threatening the lives of business rivals, illegally wiretapping a government official, and taking part in extortion and racketeering." It also alleges Deripaska ordered the murder of a businessman rival and has links to a Russian organized crime group.

In 2005, Deripaska hired Paul Manafort, Donald Trump's former campaign manager, to promote Russian interests in politics and business in Europe and the United States. The contract paid Manafort $10 million.

Manafort has since been jailed in the U.S. He was indicted in October 2017 on multiple charges arising from his consulting work for the pro-Russian government of former president Viktor Yanukovych of Ukraine. This August, Manafort was convicted on eight out of 18 charges of tax and bank fraud.

Deripaska has a controlling interest in EN +, owns a controlling interest in United Company RusAl; owns the largest independent Russian power producer, EuroSibEnergo (ru), and is a supplier of ferromolybdenum. He also has significant coal assets and logistics business.

RusAl is the world's largest aluminum producer outside of China. Automaker GAZ is also part of Deripaska's business empire. The Treasury Department said a deadline of Oct. 23 remains in force for investors to divest their holdings in the GAZ Group.

U.S. Treasury Secretary Steven Mnuchin, however, said the United States is in talks with Rusal to remove it from the U.S. sanctions list.

"EN+ and Rusal have approached the U.S. government about substantial corporate governance changes that could potentially result in significant changes in control," said Treasury in a statement. To allow sufficient time for review, Treasury is extending these licenses until Nov. 12.

The Russian businessmen included in the U.S. sanctions list last April include Gazprom CEO Alexei Miller; Surgutneftegaz CEO Vladimir Bogdanov; Sibur board member Kirill Shamalov; businessmen Igor Rotenberg and Suleiman Kerimov; VTB head Andrei Kostin; owner of Renova Viktor Vekselberg, and Deripaska.