In this article for Mealey's International Arbitration Report, Margarita R. Sánchez and Maria Lapetina provide their insights on the practice of "double hatting."

"Double hatting" refers to the practice in which an arbitrator assumes the role of counsel in additional disputes, which may or may not be connected to the claims they are currently arbitrating. "Double-hatting is controversial, particularly in the context of investor-state dispute settlement (ISDS)," said Sánchez and Lapetina. "And, as a result, there has been ongoing discussion and debate about whether and how to prohibit, restrict, or regulate the practice, in order to safeguard international arbitration proceedings."