Project area B focuses on new challenges in the design and regulation of markets. The deregulation and internationalization of markets and the development of new technologies, notably the internet, have radically changed the conditions under which economic transactions take place and, in particular, have given rise to new forms of economic exchange. Important activities now routinely take place in two-sided markets where platforms play a key role as intermediaries between the two sides, often buyers and sellers. The network externalities that distinguish platform markets from traditional markets raise new questions as to how markets should be regulated, in particular with respect to merger control and antitrust, and how much and in which form consumers should be protected by regulatory intervention. The mobile internet, in particular, and the advances of information technology, more generally, have also changed the informational environment in which economic transactions take place. Search and price comparison sites, as well as social media, have facilitated product comparisons and the acquisition and sharing of product information. In order to understand the efficiency properties of informationally sensitive markets, and to devise appropriate regulatory measures, project area B analyzes both the information providers’ strategic incentives to disclosure information and users’ search and information acquisition behavior.