AfterQuery reportedly becomes Y Combinator’s fastest-ever unicorn, now valued at $3.2B

AI training-data startup AfterQuery has reached a $3.2 billion valuation just five months after its Series A round, marking the fastest unicorn growth in Y Combinator history. The company differentiates itself by training AI models to emulate the decision-making patterns of professional experts.
Why it matters
The rapid valuation reflects the intense investor interest in specialized AI training data and the evolving business models within the generative AI sector.
AI training-data startup AfterQuery has reportedly raised a round that valued it at $3.2 billion. This just five months after announcing its $30 million Series A at a $300 million valuation in April.
That’s more than a 10x increase in less than half a year and, according to Y Combinator partner Gustaf Alströmer, the fastest that any startup has gone from launch to unicorn status in the accelerator’s history. AfterQuery’s founders, today 22 and 23 years old, attended Y Combinator’s Winter 2025 cohort, just 18 months ago.
In April, the San Francisco startup said it had reached an annualized revenue run rate of $100 million and that it was working with many of the biggest labs. It has named companies including Nvidia, Legora and the Korean AI lab Motif Technologies, as customers.
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