Understanding how to build business models for start-ups in nascent markets is a significant issue that has increasingly caught the attention of both scholars and practitioners. Most existing studies focus on the business models of mature enterprises in traditional settings, with little research having been conducted so far on the business model mechanisms of start-ups in nascent markets. To fill this gap, we used data collected through in-depth interviews with entrepreneurs of six Chinese nascent internet start-ups. This is then summarised and refined following several main theoretical categories: entrepreneurial cognitive schema, cognitive model, cognitive flexibility, interaction stage, and business model results. Findings suggest that management cognition - a subjective variable involved in start-up business model building - explains why start-ups with disadvantages in experience and networking can achieve even better entrepreneurial outcomes.