Platforms are the critical players driving the digital economy. My thesis focuses on the platform economy, especially the competitive advantage of platforms. On the one hand, what factors affect the competitive advantage of platforms? How does the platform form the competitive advantage? These questions are related to platform strategy. On the other hand, does the competitive advantage of platforms harm social welfare? This question is related to regulatory issues. The first chapter of my dissertation studies how different aspects of user effects drive value in two-sided markets. We first develop a model of inter-temporal network effects and within-period network effects of users to estimate different aspects of user effects. We then propose a model to estimate the user lifetime value in two-sided markets and examine the effectiveness of the user growth strategy. Finally, we discuss platform heterogeneity and corresponding platform strategies. Using Groupon data, we empirically estimate different aspects of user effects and examine how they vary. We show that the strength of the inter-temporal same-side network effect affects user stickiness, further influencing the persistence of the within-period cross-side network effect. Strong within-period cross-side network effects alone cannot sustain value creation. Our findings remind managers not to overemphasize user growth when the inter-temporal network effects are weak and should instead focus on platform design that increases user stickiness. The second chapter of my dissertation examines the impact of a potential policy of opening a platform's big data to banks on FinTech lending. We show that the policy promotes competition in FinTech lending and the loan price decreases. However, its impact on financial inclusion is unclear. We discuss how the efficiency of the banking system and the value of big data affect the policy outcome. We also consider the equilibrium of a data market where the platform can sell big data to banks. We show that FinTech can best promote financial inclusion in this case, but the loan price is the same as when the platform monopolizes big data. Since financial inclusion is important for entrepreneurship and innovation, the regulator should carefully examine the context in their countries before making a policy choice. The third chapter of my dissertation studies the impact of cross-market acquisitions of giant platforms on start-ups' entry into emerging markets. Our model shows that the acquisition reduces the post-acquisition entry but may increase the pre-acquisition entry. The net effect of the acquisition on the entry is positive when the pre-acquisition gain is greater than the post-acquisition loss. We then discuss three cases in which a giant platform strategically increases its market position in the acquisition. The net effect of the acquisition on start-ups' entry varies in different cases. Our findings indicate that regulators should analyze the specific situation of each acquisition before making a decision to approve an acquisition.

Despite its benefits, online peer-to-peer lending bears the risks associated with traditional forms of institutionalised lending. However, because individuals have taken over the role of the institutional lender, and the institutional participant in this form of lending takes a step back by acting only as an intermediary between the borrowers and lenders, ordinary individuals are left to bear the type of risks that institutions have traditionally borne, but without the same means of doing so. There has been little academic analysis of the role and form that regulation should take in the regulation of peer-to-peer lending and most discussions centre on the American regulatory experience. This thesis sets out to examine the theoretical classification of online peer-to-peer lending and the theoretical and practical justifications for regulating it. The aim is to ascertain the most appropriate way to regulate peer-to-peer lending, taking into account the underlying conceptual model which underpins it. The study adopts a theoretical analysis of P2PL participants and regulation based on the concepts of consumer protection and paternalism. It includes a doctrinal analysis of the UK peer-to-peer lending legislation and regulation to identify, describe and explain the rules pertaining to the industry. It also uses a comparative approach to compare P2PL with existing forms of financial lending and similar (dis)intermediated forms of transacting between individuals to show that online peer-to-peer lending is a unique form of intermediated transaction. The thesis argues that it is important that regulation displays an understanding of the underlying conceptual framework of the business model it aims to regulate. In doing so, it also argues that the peer-to-peer lending users are more than just ‘consumers’. They demonstrate a shift in the conception of individuals from consumers to prosumers because they participate in the production side of the services they receive. It goes further than existing discussions of prosumption by positing the concept of the ‘lendsumer’ to give a more accurate account of the role and experiences of peer-to-peer lenders and the effect this has on their transactional relationships and the risks they face because of this role. Based on this analysis, the thesis shows that the UK regulatory regime has limited suitability because it lacks awareness of the underlying prosumption model of peer-to-peer lending, focusing only on the business-to-consumer aspects. Consequently, it does not resolve all the issues resulting from the tripartite, participatory nature of the peer-to-peer lending transaction. In light of these findings, the thesis proposes the regulatory use of two main concepts and highlights their implications for peer-to-peer lending regulation. The first is the ‘lendsumer’ as a new paradigm of the consumer which has implications for the regulatory protections afforded to the P2P lenders. The second is the use of gatekeeper liability, adapted to online peer-to-peer lending, as a way to affect these protections in light of the particular vulnerabilities and risks experienced by the peer-to-peer lender.