Bill Gates's youngest daughter Phoebe builds AI startup targeting unicorn status without billionaire parents' backing

Phoebe and her co-founder Sophia Kianni, a former roommate at Stanford University, last week raised a US$35 million Series A round led by Notable Capital. The startup has now raised more than $43 million in total funding at a $185 million valuation and has more than one million users.

"We are sitting on top of a trillion-dollar opportunity being the agent that determines what women buy," Phoebe said in a recent interview with Forbes. "We wanted to have the capital, frankly, to be able to incentivize the best talent in the game."

Launched in April 2025, Phia uses artificial intelligence to compare clothing prices across more than 40,000 websites, helping users identify the best deals. It initially began as a browser extension that scanned the web for resale comparisons on items shoppers were viewing. While the early version did not perform well, Phoebe said continued user interest convinced her the concept had potential.

Bill Gates and daughter Phoebe Gates. Photo courtesy of Bill Gates' Instagram

She and Kianni later rebuilt the product as a standalone app and began raising funding. Their first $250,000 investment came from a university professor. The co-founders later joined the Soma Fellowship, a program that has backed more than two dozen unicorns, including Kalshi, founded by the world’s youngest self-made female billionaire, and Mercor, created by the world’s youngest self-made billionaires.

Phia has since attracted celebrity investors such as Kris Jenner, Sara Blakely, and Hailey Bieber, alongside major backers including Kleiner Perkins and Michael Rubin. Despite her background, Phoebe did not seek financial support from her father.

In an interview with The New York Times last year, the Microsoft-cofounder said it was "lucky" that way, adding that he would have kept her "on a short leash" with business reviews, which he believed would have been complicated by parental bias.

Melinda, the billionaire philanthropist, has also said that Phoebe raised funding independently and that she did not invest in the startup herself, according to the New York Post. "I wouldn’t put money into it," she said, explaining that it was important for Phoebe, as a female entrepreneur, to learn how to raise capital on her own and "have the courage to play the game and to stick with it."

As Phia matures, Phoebe said transparency and data discipline become increasingly important when dealing with investors. "The later stage that you get as a company and the further you are in your funding journey, the more this is very much a data-oriented process," she said.

While early rounds focused on proving product-market fit, she noted that discussions now center on whether the business can realistically scale into a unicorn.

"As your business grows and matures, you [must be] able to distill everything into a simple business model and financial model to understand how it can become a multi-billion dollar business."