AI startup AfterQuery has raised a funding round valuing it at $3.2 billion, just five months after its $30 million Series A at a $300 million valuation. This marks a more than 10x increase in under six months, making it the fastest startup to reach unicorn status in Y Combinator's history, according to partner Gustaf Alströmer.

Founded by 22- and 23-year-old entrepreneurs who went through Y Combinator's Winter 2025 cohort, AfterQuery reported an annualized revenue run rate of $100 million in April. The company counts major clients including Nvidia, Legora, and Korean AI lab Motif Technologies.

AfterQuery is part of a new wave of startups, alongside Mercor and Scale, that employ knowledge professionals such as doctors and lawyers for model training. However, AfterQuery differentiates itself by focusing on teaching models to complete tasks like professionals, rather than just answering questions accurately.

The company describes its approach as "encoding the patterns, decisions, and reasoning of the world’s best practitioners." Forbes first reported the news, but AfterQuery has not yet commented publicly.