Famously Obstinate, Bill Ackman Is Now Real-Life Famous. What Next?

In June 2017 — as he was reeling from the end of his marriage of more than two decades and some of the most disastrous investments of his career — Bill Ackman, the billionaire hedge-fund financier, joined Twitter.

In his few posts that year and the next, Mr. Ackman, now 57, shared a picture of himself posing in line at the fast-food chain Chipotle, one of his largest investments; links to position papers on another investment, ADP; and a news release announcing the winners of his foundation’s awards. He offered his early Twitter followers little of the drama that was part of his investing style and would later become a hallmark of his round-the-clock social media posts.

Just a few months later, Mr. Ackman went on his first date with a Massachusetts Institute of Technology professor, Neri Oxman. He was instantly smitten, and asked her on that date if she was open to having children, he told the crowd last year at an awards dinner.

By 2018, at his annual investor meeting for his hedge fund Pershing Square, he told investors he was certain his firm’s performance, which had been suffering, would turn around because he was in love with Dr. Oxman. They married the following year.

And yet, it was arguably the other new relationship in his life that helped him past his professional rut: Twitter.

Mr. Ackman has credited his use of the platform with helping him see around corners during the pandemic. His $27 million bet against the market became $2.7 billion in a matter of weeks in early March 2020. (Forbes calculates his net worth at $4.3 billion.)