AfterQuery Becomes Y Combinator’s Fastest Reported Unicorn With $3.2B Valuation

AI training-data startup AfterQuery has reportedly reached a $3.2 billion valuation, just five months after announcing a $30 million Series A round at a $300 million valuation.

The rapid increase would represent more than a tenfold jump in valuation in less than half a year. According to Forbes’ report, the company has become Y Combinator’s fastest startup to reach unicorn status, according to Y Combinator partner Gustaf Alströmer.

AfterQuery Builds AI Training Data for Professional-Level Tasks

AfterQuery was founded by entrepreneurs who participated in Y Combinator’s Winter 2025 cohort. The company’s founders are now 22 and 23 years old, and the startup was launched only about 18 months ago.

In April, AfterQuery said it had reached a $100 million annualised revenue run rate and was working with several major AI labs. The company has identified organisations, including Nvidia, Legora, and the Korean AI company Motif Technologies, as customers.

The startup belongs to a growing group of AI companies focused on improving model training through expert knowledge. Similar to companies such as Mercor and Scale, AfterQuery works with professionals including doctors, lawyers, and specialists to help train artificial intelligence systems.

However, AfterQuery focuses on teaching models how professionals approach complex tasks rather than only improving factual accuracy. The company describes its approach as capturing the patterns, decisions, and reasoning used by leading practitioners.

Startup Joins Growing AI Training Data Market

The reported valuation reflects growing investor interest in companies that provide specialised data and expertise for developing advanced AI systems. AfterQuery has positioned itself as a provider of training for AI models and agents to perform tasks using professional workflows and decision-making patterns.

The company’s latest funding round has not been publicly detailed beyond the reported valuation. AfterQuery’s rapid growth places it among the newer AI startups attracting significant attention from investors and the broader technology industry.