January 12, 2018
Pickens rose to national prominence in the 1980s when he led a series of takeover attempts, targeting Phillips Petroleum, Unocal and Gulf Oil, among other companies.
He's also given away more than $1 billion to philanthropic causes, according to Rosser.
Pickens said in the statement that he will continue to engage in philanthropy and politics and to provide his perspective on energy and cultural issues.
He hosted a fundraising meeting of America First Action, a pro-Trump super PAC, at his ranch in October. He plans to host a summit to discuss a planned veterinary school at Texas Tech University at his ranch later his month, Rosser said.