AfterQuery Emerges as Y Combinator’s Fastest Unicorn, Now Valued at $3.2 Billion

AfterQuery, an innovative AI training-data startup, has achieved a remarkable milestone by raising funds that have positioned its valuation at $3.2 billion. This surge comes just five months after the company announced a $30 million Series A funding round that valued it at $300 million back in April.

This swift growth represents over a tenfold increase in valuation within a mere six months. According to Gustaf Alströmer, a partner at Y Combinator, AfterQuery has set a record as the fastest startup ever to transition from inception to unicorn status in the accelerator’s history. The founders, aged only 22 and 23, participated in Y Combinator’s Winter 2025 cohort just a year and a half ago.

In its April announcement, the San Francisco-based company reported achieving an annual revenue run rate of $100 million and stated that it was collaborating with several prominent labs. It has identified major clients, including Nvidia, Legora, and Motif Technologies, a leading South Korean AI lab.

AfterQuery is positioned among a new wave of startups following in the footsteps of companies like Mercor and Scale, focusing on harnessing knowledge professionals—such as doctors and lawyers—for model training. Unique to AfterQuery is its approach, emphasizing the training of models and agents to perform tasks using methodologies adopted from the best professionals in the field, which the company refers to as “encoding the patterns, decisions, and reasoning of the world’s best practitioners.”

The funding round was first reported by Forbes, and as of now, AfterQuery has not provided further comments on the matter.