Financial documents reveal that the rapid growth of AI startup Mercor is heavily dependent on a small number of large AI companies. In the first half of 2026, approximately 91% of Mercor's $614 million in revenue was generated from foundational AI model developers. The company's core clients include OpenAI, Anthropic, and Google DeepMind. Mercor, a private company reportedly seeking a new funding round at a valuation that could reach $20 billion, provides a marketplace of human experts to train and evaluate AI models. This high client concentration is a central risk in its funding discussions, as the potential loss of a major partner could significantly impact its business. The company has stated it plans to diversify its revenue by expanding its base of enterprise clients.