This paper explores the institutionalization process of complementary currencies; understanding the institutionalization of alternative economies is key in order to assess their sustainability. Drawing from neo-institutional theory, the paper examines the objectification processes in a sample of Spanish and Greek recently formed time banks. The paper focuses on the rationalization stage, i.e. when rules, practices and symbols are embedded in the organization, and studies how symbols and norms establish the framework for social interaction and make the common space of action visible. The main finding of this paper is that timebanking is subject to multiple logics, both inter and intra time banks. These logics lead to adopt different organizational forms, promote disparate forms of actorhood, and adopt different pricing and accounting systems. Yet, these objects are not aligned with one another, and tensions between the symbolic and the functional are found. Institutionalization is not yet complete as there are still missing blended models that bridge multiple logics.