Robert Mercer, the billionaire co-chief executive of hedge fund Renaissance Technologies LLC and an early backer of Donald Trump during his presidential campaign, is resigning from his role, according to a memo sent to employees on Thursday.

Who is Mercer?

Mercer, 71, and his daughter Rebekah, came to public attention during the 2016 presidential campaign, when they donated early and generously to Trump and encouraged him to add Steve Bannon and Kellyanne Conway to his staff.

Mercer is also a part owner of Cambridge Analytica, a private company that uses data mining and analysis in election campaigns. The company is credited with influencing voters in the Trump election as well as the Brexit campaign and has become the subject of criminal probes in both countries.

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Mercer said he will depart the hedge-fund role on Jan. 1.

What does the memo tell us about Mercer’s politics?

“Of the many mischaracterizations made of me by the press, the most repugnant to me have been the intimations that I am a white supremacist or a member of some other noxious group,” Mercer wrote in his memo.

Instead, he is a strong believer in individuals forming their own opinions and taking responsibility for their actions, rather than being swayed by experts “who are confident in their knowledge of what is best for everyone else. This is why I support conservatives, who favor a smaller, less powerful government,” he wrote.

Mercer is unhappy that the media has characterized his political views as matching those of Bannon.

“I have great respect for Mr. Bannon, and from time to time I do discuss politics with him. However, I make my own decisions with respect to whom I support politically. Those decisions do not always align with Mr. Bannon’s,” he wrote in the memo.

The individual he singles out for the most criticism is Milo Yiannopoulos, the former Breitbart tech editor and Bannon protégé who is widely credited with inciting internet trolls in the Gamergate controversy and other social media attacks.

Yiannopoulos, a conservative firebrand, has expressed views that are critical of feminism, Islam, social justice and political correctness. He was banned from Twitter in 2016 for “inciting or engaging in the targeted abuse or harassment of others”. An October report revealed his contacts with extreme-right and neo-nazi groups, including seeking feedback and story ideas while working for Breitbart. Leaked emails showed that many of his articles were written by other people.

Yiannopoulos was fired from Breitbart and had a book contract with Simon and Schuster canceled after the release of a video clip in which he appeared to condone sexual relationships between teenage boys and adult men. More recently, speeches made at U.S. universities have attracted protests and violence with eight people being arrested at Cal State Fullerton this week after he spoke on the suppression of conservative views on campuses.

Mercer said he supported Yiannopoulos in the hope and expectation that by expressing views that went counter to mainstream and “spotlighting of the hypocrisy of those who would close down free speech in the name of political correctness" would promote open debate on U.S. campuses.

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“But in my opinion, actions of and statements by Mr. Yiannopoulos have caused pain and divisiveness undermining the open and productive discourse that I had hoped to facilitate. I was mistaken to have supported him, and for several weeks have been in the process of severing all ties with him,” he wrote in the memo.

Milo Yiannopoulos Resigns From Breitbart News

Renaissance Technologies has become a subject of an activist online organization called Sleeping Giants, that has been lobbying universities and pension funds to pull their money because of Mercer’s ties to alt-right website Breitbart News and to far-right figures, including Milo Yiannopoulos, according to The Street.

Why is he leaving his job?

Mercer said he is not planning to retire, but to relinquish management responsibilities and resign from the board. He will continue to work the firm on the research side, work “that I find most fulfilling.”

The investor has also decided to sell his stake in Breitbart News to his daughters.