Lucy Guo is an American entrepreneur and investor best known as co-founder of Scale AI (2016), the San Francisco startup that supplies labeled data and evaluation infrastructure to train and test AI models. In 2025 she hit mainstream business headlines when Forbes placed her on its America’s Richest Self-Made Women list at age 30, citing wealth tied largely to her early Scale equity.
Early life, education and the Thiel Fellowship
Guo grew up in California and studied computer science and human–computer interaction at Carnegie Mellon University before dropping out after winning a Thiel Fellowship (a $100,000 grant to build companies instead of finishing college). She interned at Facebook and worked as a product designer at Quora and Snapchat before founding her own companies.
Co-founding Scale AI (2016)
In 2016, Guo co-founded Scale AI with Alexandr Wang. Scale built human-in-the-loop platforms — later adding synthetic data and model-evaluation tools — that enterprises and leading labs use to improve AI systems. As generative-AI spending surged, Scale’s profile — and Guo’s stake — rose sharply. In May 2024, the company raised $1 billion led by Accel, with Nvidia, Amazon and Meta participating, valuing Scale at about $13.8–14 billion.
In 2025, coverage of Scale’s fast-moving competitive environment included a trade secrets lawsuit the company filed against a newer rival — underscoring the high stakes around data, tooling and talent in AI infrastructure. The litigation does not involve Guo directly.
Valuation context. Through mid-2025, reputable reporting anchored Scale’s last confirmed round near $14 billion (May 2024). Any larger 2025 deal talk was framed as exploratory.
Quick timeline
- 2014 — Wins Thiel Fellowship; leaves CMU.
- 2016 — Co-founds Scale AI with Alexandr Wang.
- 2018 — Exits day-to-day at Scale; retains equity.
- 2019 — Launches Backend Capital (seed-stage venture).
- 2022 — Founds Passes (creator monetization).
- Feb 2024 — Passes raises $40 million Series A led by Bond.
- May 2024 — Scale AI raises $1 billion at ~$14 billion valuation.
- Apr–Jun 2025 — Wealth-list coverage cites Guo as youngest self-made woman billionaire.
- Mar–Aug 2025 — Passes faces lawsuits; Guo disputes claims and seeks dismissal.
Leaving Scale, staying an owner
Guo left day-to-day work at Scale in 2018 but retained a material equity position. Business press in 2025 repeatedly tied her paper wealth to that stake, with Forbes and Fortune highlighting her as the youngest self-made woman billionaire based on private-market marks and list methodology.
Investor and company builder: Backend Capital and Passes
After Scale, Guo launched Backend Capital (2019), a seed-stage venture franchise investing in engineering-led startups.
In 2022, she founded Passes, a direct-to-fan creator-monetization platform that positions itself as brand-safe while offering CRM-style tools. In February 2024, Passes announced a $40 million Series A led by Bond (Mary Meeker/Mood Rowghani), with several high-profile co-investors; Fortune cast the raise as part of Guo’s “second act.”
Legal headwinds around Passes
In 2025, Passes faced lawsuits alleging mishandling of under-18 creators. Guo publicly denied the allegations and moved to dismiss the claims, calling them meritless and contrary to Passes’ policies. Trade and mainstream outlets covered both the filings and the company’s responses.
Public profile and recognition
Guo’s visibility spiked in 2025 as financial and tech media profiled her arc — from CMU drop-out and Thiel Fellow to Scale co-founder and Passes CEO — alongside wealth-list debate. Local business journals also featured her on executive roundups.
