Lucy Guo, the 30-year-old co-founder of high-flying A.I. startup Scale AI, just dethroned Taylor Swift as the youngest self-made female billionaire. With a net worth nearing $1.3 billion, Guo landed at No. 26 on Forbes’ annual “America’s Richest Self-Made Women” list, published yesterday (June 3).

Raised in Fremont, Calif. by Chinese immigrant parents, Guo was “always an entrepreneur growing up,” she said in a 2023 interview—selling Pokémon cards and colored pencils in kindergarten. By second grade, she was coding; soon after, she was building bots that made her thousands. In 2014, at just 20 years old, she dropped out of Carnegie Mellon University, where she studied computer science, after receiving the Thiel Fellowship. The program, backed by billionaire investor Peter Thiel, offers $200,000 over two years to help promising college students build companies—on the condition they leave school behind.

Around that time, she interned at Facebook, had a brief stint at Quora in 2015, and then became Snapchat’s first female product designer, working full-time for a year. At Quora, she met Alexandr Wang, a math prodigy two years younger who rose quickly at the company. In 2016, the two founded Scale AI—initially as a healthcare platform matching patients with doctors for specific procedures. The concept earned them admission to Y Combinator’s summer 2016 batch.

A friend at Y Combinator floated the idea of building an “API for Humans”—a streamlined way for people to exchange data at scale. The concept stuck. It quickly attracted funding from Accel and morphed into Scale AI’s core business: supplying the high-quality, labeled data that powers A.I. systems. By employing thousands of contractors to annotate images and data points, Scale AI helps companies like Tesla train their models to recognize everything from pedestrians to roadblocks.

Guo was ousted from Scale in 2018, reportedly after a disagreement with Wang, who still serves as CEO. She kept a roughly 5 percent stake—an asset that’s aged well. Scale AI is currently valued at $25 billion after closing a fundraising round earlier this week.

“I don’t really think about it much, it’s a bit wild. Too bad it’s all on paper haha,” Guo told Forbes via text in response to her new billionaire status.

Her co-founder, who owns 15 percent of Scale AI, has been the world’s youngest self-made billionaire since 2022, currently boasting a net worth of $3.6 billion.  

While Guo insists most of her fortune exists only on paper, she hasn’t exactly been living modestly. Last year, she bought a $4.2 million designer home in Los Angeles and also owns a $6.7 million apartment in Miami. At the latter, she hosted a party featuring exotic animals that reportedly irritated fellow residents, including David Beckham. In 2022, the New York Post anointed her “Miami’s number one party girl.”

Since parting ways with Scale AI, Guo has stayed busy. She founded Backend Capital to invest in early-stage startups, backing hits like Ramp, the financial software firm now worth $13 billion. Not long after, she raised $50 million between 2022 and 2024 for her next act: Passes, a pay-for-content platform she founded and now runs as CEO. The platform attracted major names like Shaquille O’Neal and DJ Kygo, offering fans exclusive access to celebrity content. But controversy soon followed: Passes was accused of enabling underage sexual content. Prior to the allegations, the company had already banned underage creators and scrubbed all associated content.