AfterQuery, an AI training-data startup and Winter 2025 Y Combinator cohort participant, has reportedly achieved unicorn status with a $3.2 billion valuation. Remarkably, this milestone came just five months after its $30 million Series A funding round valued the company at $300 million. According to Y Combinator partner Gustaf Alströmer, AfterQuery is the fastest startup in Y Combinator's history to reach a billion-dollar valuation since launch.

The San Francisco-based company, co-founded by two young entrepreneurs aged 22 and 23, has quickly scaled its business. By April 2026, AfterQuery had reached an annualized revenue run rate of $100 million and secured significant clients such as Nvidia, Legora, and Motif Technologies, a Korean AI lab. The startup specializes in teaching AI models how to approach tasks by mimicking the skills and reasoning of top professionals like doctors and lawyers.

AfterQuery differentiates itself from other model training startups by focusing on training AI and agents to complete tasks in a professional manner rather than simply improving the accuracy of responses. The company describes its mission as “encoding the patterns, decisions, and reasoning of the world’s best practitioners,” allowing AI systems to perform at expert levels across different domains. This innovative approach has helped it rapidly gain attention and investment in the competitive AI market.

While Forbes initially reported the fundraising round, AfterQuery refrained from commenting at the time of the TechCrunch article’s publication on September 1, 2026. The company joins a growing cohort of startups transforming artificial intelligence through unique applications of human expertise, further fueling investor enthusiasm and the broader AI ecosystem's growth.