Inside the meteoric rise of Mercor

"In the race to build superintelligent AI, high-caliber data is everything. Mercor, a data annotation startup, has emerged as one of the fastest-growing companies in history by offering something most rivals don't: expert-labeled evaluations that benchmark the capabilities of large language models. AI evaluations ("evals") are structured assessments that measure how well a model performs on tasks within specific domains."

"Instead of low-wage workers tagging data, Mercor hires doctors, engineers, lawyers, investment bankers, and other professionals to judge model outputs for quality and accuracy. A software engineer, for instance, might evaluate code for security flaws or functional completeness, then design a rubric developers can use to benchmark improvement. Those rubrics become the scoring guides that machine learning engineers deploy to grade model responses, flag failures, and define what a "good" answer looks like."

"Since launching in January 2023, Mercor has inked deals with frontier model developers like OpenAI and Anthropic, as well as six of the "Magnificent Seven" tech giants, including Alphabet, Amazon, and Google. In just 17 months, Mercor saw its annual revenue run rate surge from $1 million to $500 million. The company claims it now employs more than 30,000 experts, paying contractors an average rate of $95 an hour to test and score model performance. As of October 2025, Mercor's valuation sits at $10 billion, with investments from Felicis, Benchmark and General Catalyst."

Mercor builds domain-specific, expert-labeled evaluations to benchmark and improve large language model performance. Mercor replaces low-wage annotators with professionals such as doctors, engineers, lawyers, and investment bankers to judge outputs for quality and accuracy. Experts create rubrics and scoring guides that machine learning engineers use to grade responses, flag failures, and define acceptable answers. Engineers can test code for security flaws or completeness and translate findings into measurable benchmarks. Since January 2023, Mercor secured contracts with frontier model developers and major tech firms, scaled to tens of thousands of experts, achieved rapid revenue growth, and reached a multibillion-dollar valuation.

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