Today, instead, it’s a distinction held by Luana Lopes Lara, the 29-year-old Brazilian cofounder of Kalshi. The prediction market raised $1 billion in December; a new $11 billion valuation pushed Lopes Lara’s own net worth to $1.3 billion. She dethroned Scale AI cofounder Lucy Guo, 31, for the honor. (When Lopes Lara earned the title, Guo DMed her, but they haven’t met yet.) Last month, Kalshi doubled its valuation again to $22 billion with $1 billion in reported new financing—we can expect Lopes Lara’s stake to double in value, too.

Inside Kalshi’s downtown Manhattan office, it would be hard to pick out the world’s youngest female billionaire from everyone at their desks. Lopes Lara has a low-key aesthetic. Her whole thing is hard work: she’s a former competitive ballerina, who trained for years at Brazil’s uber-competitive Bolshoi Theater School (Forbes reported that her teachers held lit cigarettes under her thigh to test how long she could hold her leg up). She describes herself as a “very intense person” who is all-or-nothing on everything from building a company to working out. She and her cofounder, Kalshi CEO Tarek Mansour, both worked at Citadel before founding the company and gave up high-paying quant jobs to pursue the idea.

Alongside Polymarket, Kalshi is fueling the rise of prediction markets. These platforms allow users to trade (or bet) on everything from elections to who’s going to win Dancing With the Stars. How is it different from gambling? “We have no house,” is how Lopes Lara explains it. My colleague Jeff John Roberts recently published a piece examining the potential for insider trading on these largely unregulated platforms. Kalshi has positioned itself as more dedicated to compliance than its rival Polymarket. Lopes Lara emphasizes the usefulness of the probability distribution data Kalshi collects on the world’s most significant events.

Inside the company, Lopes Lara leads everything internal, from product design and engineering to general operations. Mansour is focused on external-facing work like regulatory compliance and investor relationships.

Lopes Lara says her life hasn’t changed in the almost four months she’s been the world’s youngest female self-made billionaire. “It was pretty surreal,” she says. “But it doesn’t change anything at all. It’s just company stock. … [After an IPO], I guess I’ll be liquid, but right now it doesn’t change anything in my life.” “I’m still here 12 hours a day, working very hard trying to build this into a way bigger company,” she adds.

She doesn’t seem especially impatient for that moment to arrive. “With ballet, everything’s about delayed gratification,” she reflects. “I’m going to work hard a full year so that I have 30 seconds on stage. I’m going to be in pain so I can get those 30 seconds. So for me, it’s very natural to think about things like—it’s going to be a very hard three years, but if it works out… that’s something I’m comfortable with.”

Emma Hinchliffe
emma.hinchliffe@fortune.com

The Most Powerful Women Daily newsletter is Fortune’s daily briefing for and about the women leading the business world. Subscribe here.

ALSO IN THE HEADLINES

The WNBA is getting three more teams. The league just officially approved expansion teams in Cleveland, Detroit, and Philadelphia. Between 2024 and 2030, the league will have expanded from 12 to 18 teams. Eighteen is a record, past the 16 that played in the early 2000s. 

Melania Trump called a press conference about Jeffrey Epstein. The first lady delivered remarks in which she said she had no relationship with him, was not a victim of his and had no knowledge of his crimes. She said she was responding to "numerous fake images and statements" about her and Epstein. But as the NYT put it: "It was not clear why she chose to speak out now, or to what reports she was referring." 

Jo Malone is fighting for her name. Estée Lauder Companies, which bought Jo Malone (the brand) in 1999, is suing Jo Malone (the woman) for using her name on fragrances she created for Zara. The fragrances say "A creation by Jo Malone CBE, founder of Jo Loves." ELC is attempting to recover more than £200,000 in damages. 

Mormon culture is becoming big business. The dirty soda chain Cool Sips tapped Secret Lives of Mormon Wives star Whitney Leavitt as it brings the drinks popular in Utah to new U.S. markets. 

ON MY RADAR

What leading Planned Parenthood is like now The 19th

Fleur du Mal founder Jennifer Zuccarini wants to shock you Vogue Business

More than a decade later, Venus et Fleur is thriving Glamour

PARTING WORDS

"It's insane. I would never do it now."

— Lisa Kudrow on how she went back to work 10 days after having a baby in 1998