AfterQuery Becomes Y Combinator’s Fastest Unicorn, Valued at $3.2 Billion

AfterQuery, a startup specializing in AI training data, has reportedly secured funding that boosts its valuation to $3.2 billion, just five months after announcing a $30 million Series A funding round that valued the company at $300 million in April.

This reflects a remarkable increase of over 10 times in less than six months and, as noted by Y Combinator partner Gustaf Alströmer, signifies the swiftest rise to unicorn status for any startup in the accelerator’s history. The founders of AfterQuery, aged 22 and 23, were part of Y Combinator’s Winter 2025 cohort only 18 months ago.

In April, the San Francisco-based company revealed an annualized revenue run rate of $100 million and highlighted its partnerships with several esteemed laboratories. Notable clients include major firms like Nvidia, Legora, and Korea’s AI lab Motif Technologies.

AfterQuery is part of a new generation of startups, drawing inspiration from Mercor and Scale, that collaborate with professionals, such as doctors and lawyers, for model training. Rather than solely focusing on providing accurate answers, AfterQuery aims to prepare models and agents to function like experienced professionals in order to complete tasks—what the company describes as “encoding the patterns, decisions, and reasoning of the world’s most skilled practitioners.”

Forbes was the first to cover this funding round, and AfterQuery has yet to provide a response to immediate comment requests.