This study focuses on the interactions amongst angel group members to explore the role of discussions between members about the categories associated with the quality of venture and the funding potential in reaching final individual-level decisions during the investment process. Data were obtained from case archival material as in-depth interviews with group investors who made an offer, prospective investors who rejected the opportunity, as well as entrepreneurs who were funded. Results provide insights into the interactions and discussions about the venture quality against the categories amongst group members, playing a quality certification role in due diligence. Such discussions are concentrated on some categories that members have concerns with, lead to thorough evaluation results. We also show that the criteria used vary depending on each member, which are associated with the background and the level of engagement with due diligence. Social contagion actually plays an essential role in making the investment decisions for inexperienced, first-time investors or those with a difficulty in coming up with conclusive evaluation against some categories.