We are currently witnessing a global transition (albeit slow) towards new, more sustainable models of development and consumption. This transition activates and highlights a series of discrepancies between the various actors in agri-food marketing systems, including the institutions that govern regulatory and trade aspects. These discrepancies highlight that the global agri-marketing system does not provide adequate responses to the principles of sustainability. This is due to a mixture of opportunism, information asymmetries, and ‘lock-in effects’, which create serious market failures. This, in turn, brings structural holes, in which new forms of exchange are born. We identify these as nested markets: hybrid market forms that often use new information technologies and create a new form of proximity in which reciprocity and reputation play a central role. In this article, we argue that the market is not only the place where prices and quantities are assessed. Markets are complex social spaces, where more-or-less stable relationships are formed, based on values of reciprocity and reputation that contain opportunism. This article discusses the many well-documented cases of new markets. This article argues that these new markets are characterized by a strong specificity of the resources used (that include territory, sustainability, and solidarity).