Who writes the rules of global finance? This article explains how the transnational financial policy community can influence the content of financial governance by organizing itself via a club model. This agent-centered explanation advances the concept of a club to highlight the mechanisms through which actors operate, the expertise and skills valued by this community and the way in which principles for what constitutes appropriate financial governance are derived. Evidence is provided by an investigation of the Group of Thirty, part-think tank, part-advocacy group, a hybrid organization whose members are active in both the official and private sectors. Club characteristics can be seen in the group's high profile and prestigious membership, which self-presents a strong sense of honor. The article highlights the club as a location for those traditionally understood as financial elites. It emphasizes the collective attributes of the club, such as reputational consistency of membership, but also the importance of a track record of policy work for the enduring relevance of club arrangements in agenda-setting, consensus building and establishing mechanisms for private influence in financial governance. The study draws on 80+ interviews with key stakeholders from the community, including group members, conducted between 1998 and 2010.