AfterQuery Hits $3.2 Billion Valuation, Becoming Y Combinator’s Fastest-Ever Unicorn

In brief:

• AfterQuery has reached a $3.2 billion valuation, up from $300 million five months ago, according to Forbes, which cited two people with direct knowledge of the deal.
• Y Combinator partner Gustaf Alströmer called it the fastest run from launch to unicorn status in the accelerator’s history.
• Founders Spencer Mateega, 23, and Carlos Georgescu, 22, pay doctors, lawyers, engineers, and financial analysts to generate expert judgment data for AI labs.

AfterQuery, an 18-month-old AI training data startup, has reached a $3.2 billion valuation in a new funding round, Forbes reported Monday. This massive leap represents more than a tenfold increase from the $300 million valuation the company carried just five months earlier, when it closed a $30 million Series A round.

The unprecedented speed of this growth makes AfterQuery the fastest startup in Y Combinator’s history to transition from inception to unicorn status, according to YC partner Gustaf Alströmer. AfterQuery declined to comment on the report, though one of Forbes‘ sources indicated the company is already highly profitable and has secured a lead investor for the round.

Spencer Mateega and Carlos Georgescu founded the company in February 2025, just 18 months after joining Y Combinator’s Winter 2025 batch as two high school friends with no product and no fixed idea. Mateega posted on X in July that annual recurring revenue had grown to the “hundreds of millions,” up from $100 million in April.

AfterQuery is quickly closing the gap on the
“giants.”

We’ve already grown multiples past the $100M revenue run rate cited here.

If you’re a post-training researcher or lab that needs long-horizon tasks, professional / knowledge work data, high-fidelity RL environments, code…

— Spencer Mateega (@spencermateega) July 12, 2026

The founders originally wanted to build AI agents for finance. Testing showed leading models kept failing at nuanced, professional-grade calls—not due to a lack of raw capability, but because no one had ever taught them how an expert actually reasons through a hard decision.

So they pivoted. AfterQuery now pays specialists to produce reasoning data: written, step-by-step records of how a professional works through a problem, used to teach AI models judgment instead of just facts. Nvidia has used that data to train its open-source Nemotron models, and AfterQuery also counts former OpenAI CTO Mira Murati’s Thinking Machines Lab and legal AI firm Legora as clients, according to Forbes.

The demand behind that pivot is industry-wide. Frontier labs—the companies building the most advanced AI systems—have already picked through most of the usable text on the open web. While synthetic data helps, what remains in short supply is expert judgment that only comes from real, credentialed professionals.

Other companies are chasing the same shortage from different directions. South Korean fintech Toss recently opened its 30 million users to the AI data economy through a partnership with data infrastructure firm Poseidon, paying ordinary users to record real-world data that models cannot find online.

AfterQuery is cashing in on this shortage alongside major players. Scale AI’s Alexandr Wang became the industry’s first data-labeling billionaire in 2021 at age 24, before Meta paid $14.3 billion for a 49% stake and put Wang atop its own AI lab. Rival Mercor’s founders passed Wang’s early record last October, becoming billionaires at 22.

Mateega has said AfterQuery’s edge over Mercor, which relies on an AI interviewer to staff a large contractor pool, is custom software that screens submissions for a “Goldilocks” difficulty—hard enough to challenge a frontier model, not so hard it cannot learn from the answer. AfterQuery also trains its own models on the data before selling it, to show labs the material actually moves the needle rather than asking them to take its word for it.

Mercor, for its part, is currently in talks with Nvidia for a funding round that would value it at $20 billion, doubling its $10 billion price tag from last October. AfterQuery’s round has yet to close, and the company has not named its lead investor.

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