Abstract: This chapter explores recent Fintech innovations through the lens of Ronald Coase’s classic article: The Nature of the Firm. Applying a transaction cost analysis, the chapter argues that developments in computer technology, data processing, and information networks are reshaping the manner in which financial services are produced, unsettling the boundaries separating regulated firms from outside vendors and open market transactions. These changes raise challenging questions as to the appropriate contours of regulatory perimeters as well as the structure of regulation and supervision in the many area of financial regulation. Fintech innovations also have the potential to be harnessed to serve public purposes, including expanding access to financial services and improving supervisory practices. At a minimum, Fintech innovations and most especially machine learning and artificial intelligence complicate the application of legal doctrines based on human intentionality. More broadly, the scale and scope of these technological developments may lead to a fundamentally rethinking of the appropriate goals of regulatory policy for financial firms and the economy more broadly, particularly with respect to privacy and the accumulation of personal information in private and public hands.