If you’ve heard of Bill Ackman, you probably have an opinion of Bill Ackman.
The outspoken billionaire is the founder of Pershing Square, a hedge fund that has made wildly successful bets (like Chipotle (No. 374) and Canadian Pacific Railway) and overcome epic disasters (like Valeant Pharmaceuticals and Herbalife).
When I was researching Ackman for the latest episode of Fortune 500: Titans and Disruptors of Industry, I was struck by qualities he expressed when he was young that would later shape his career.
One was his ambition. As a teenager, Ackman predicted to his dad (who gave him no allowance and declared he would never receive an inheritance) that he would become a millionaire by age 30, have $100 million by age 40, and become a billionaire by age 50. Ackman wound up hitting each of those milestones ahead of schedule.
When he started his first firm, Gotham, out of Harvard, Ackman secured financing by cold-calling moguls on the Forbes 400 list, a ranking of the wealthiest Americans. “I figured if I want to raise $10 million, why not go to the richest people in the world and ask them for a relatively small amount of money?” he told me. A few said yes.
Another attribute from Ackman’s early life that has remained constant is his unwavering conviction. A friend commented in his yearbook that “a closed mouth gathers no foot.” In the years since, Ackman has gained 2.7 million followers on X while arguably gathering many feet.
He has been loudly opinionated on a range of polarizing societal topics that stray far outside the bounds of Wall Street. As he told podcaster Lex Fridman a few years ago when he described his tussles with figures like Joe Biden and then-Harvard president Claudine Gay: “I’m attacking the president, DEI, and elite universities; I’m going to make some enemies.”
Ackman doesn’t seem to mind the blowback. He told me he gets thanked more than he gets bashed. “I’m not going to lose my job, and I can say exactly what I think,” he told me—then offered an example: “Some people are like, well, I’m not going to open a Trump Account for my child because I don’t like that it’s called ‘Trump’ Account. Okay, that’s stupid.” (Based on this Fortune overview of Trump accounts, Ackman may be right.)
In my conversation with Ackman, he made the case for recent investments in companies like Uber (No. 92) and Meta (No. 17), and why he’s bullish on Anthropic and skeptical of OpenAI ahead of the rumored IPOs. But he also delved into another investment he’s making that’s much more personal: A new brain institute in Manhattan, inspired by a family health crisis. “I’ve been very close to that issue in the last six months,” he told me. Another passion project is encouraging Americans, who are increasingly turning to socialism in the midst of the affordability crisis, to love capitalism again. “Socialism is a disaster,” he said. “Watch if Mamdani is successful in implementing these plans. Watch what happens to New York City.”
And if you don’t agree with his opinions, Ackman openly invites you to challenge him, an expectation he has of all his employees and board members.
“I’m focused on what I believe to be the truth, and I’m very happy to hear your argument if you think I’m wrong. I’ll course correct if you convince me,” he said.
Check out my full interview with Bill Ackman here. And to go even deeper, watch my first appearance on Fortune Daily, our new video show that premiered this week. Every Monday through Thursday, Fortune Daily goes behind the scenes with Fortune journalists to connect the day’s news to the bigger picture: what’s moving markets, which leaders are making the calls, and how technology and culture are transforming industries. Catch up on the latest Fortune Daily episodes and subscribe via your preferred platform here.
A version of this essay appeared in the Aug. 5, 2026 edition of Fortune’s CEO Daily newsletter. Sign up here.
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