Topline: Legendary energy tycoon and hedge fund manager T. Boone Pickens died at 91 on Wednesday after being in declining health following a major fall and a series of strokes in 2017.

Forbes ranked Pickens as a billionaire in 2013, but he soon he fell off The Forbes 400 list of the wealthiest Americans. At the time, he tweeted to his more than 110,000 followers: “Don’t worry. At $950 million, I’m doing fine. Funny, my $1 billion charitable giving exceeds my net worth.”The biggest recipient of his philanthropy has been Oklahoma State University, his alma mater. According to a Forbes profile in 2014, he had given OSU $500 million, with $165 million for the athletics department. His name is on the football stadium and the school of geology.
Usually described as a “corporate raider,” he told Forbes in 2014: “I prefer the term ‘shareholder activist.’”
Pickens was a Forbes contributor, writing about philanthropy and offering advice. Key background: Pickens followed in his father’s footsteps into the oil industry, and in 1956, he founded Mesa Petroleum. In the1980s for leading hostile takeover bids for much larger oil companies, figuring it was cheaper to get new oil from Wall Street rather than drilling.

Eventually, he left Mesa in 1996 after the company suffered from a drop in natural gas prices. That same year he started BP Capital Management, a successful hedge fund focusing on energy equities and commodities. He shifted to focus on cleaner energy sources in 2008 by launching a self-funded campaign he dubbed the Pickens Plan, which championed wind energy as a way to reduce U.S. dependence on foreign oil. Ultimately though, his $2 billion plan for a wind farm in Texas fell apart. He shuttered BP Capital in 2018, writing that he needed to focus on his health.

Crucial quote: “My timing hasn’t been perfect,” he told Forbes in 2014. “I’ve lost two billion, given away one and I’ve got one left.”

Tangent: Over his career he donated to Republican candidates, backing George W. Bush and Donald Trump during their campaigns. In 2016 he told CNN he supported Trump’s proposal to limit Muslim refugees in the U.S., saying “I’d cut off the Muslims from coming into the United States until we can vet these people.”