Is there a doctrine of 'stare decisis' in international trade and international investment law? From a positive law perspective, the answer is a definite no. However, as many scholars have observed, in practice, there has been a strong level of deference from the Appellate Body to its previous rulings, but less so from investment tribunals. Using social network analysis to assess actual citations from the Appellate Body Reports and investment arbitrations from the inception to the current time, this paper examines the evolution and 'status quo' of citation networks in international trade and international investment arbitrations. It asks, not only whether there is a 'de facto' rule of precedent in the two regimes, but also when it occurs and how the development links with the institutional design of dispute settlement. The results show how the doctrine of 'stare decisis' diverges in international trade and international investment, as well as the importance of institutional design in shaping and constraining the behaviors of tribunals.