expert-data
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Spencer Mateega
Spencer Mateega is the 23-year-old Co-Founder and CEO of AfterQuery, a San Francisco-based applied research lab that captures expert professional knowledge and converts it into high-quality training data for AI foundation models. Founded in January 2025 and backed by Y Combinator's Winter 2025 cohort, AfterQuery raised a $30 million Series A at a $300 million valuation in April 2026, with revenues exceeding $100 million annualized. Mateega's philosophy — 'We teach machines how experts think' — drives a platform connecting roughly 100,000 domain professionals in finance, legal, and software to frontier AI labs hungry for reasoning-rich data.
Alexander Ratner
Alexander Ratner is the co-founder and CEO of Snorkel AI, the company he spun out of Stanford's AI lab in 2019 after building the Snorkel open-source project during his PhD. A Harvard physics graduate turned Stanford computer scientist, Ratner pioneered the field of data-centric AI and weak supervision - the idea that better data, not just better models, is the key unlock for enterprise AI. Under his leadership, Snorkel AI reached a $1.3 billion valuation in 2025 following a $100 million Series D, with $148M in annual revenue and customers including some of the world's largest enterprises and LLM developers.