This chapter discusses vertical and horizontal problems in financial regulation and corporate governance. More specifically, it examines three contexts in which efforts to mitigate systemic risk and moral hazard in capital markets and financial institutions clash with long-standing principles of corporate governance. The first issue relates to the so-called “vertical” challenge between financial institutions and the separately incorporated holding companies that own and control them. The second issue relates to the “horizontal” challenge, in which regulatory arbitrage occurs between the banking subsidiaries of complex holding companies and their less-regulated nonbank and shadow bank siblings. The third and final issue deals with the conflict between the conception of fiduciary duty in the federal law of insider trading and the concept of fiduciary duty in state law.