We investigate the optimal regulation of financial conglomerates which combine a bank and a non-bank financial institution. The conglomerate’s risk-taking incentives depend upon the level of market discipline it faces, which in turn is determined by the conglomerate’s liability structure. We examine optimal capital requirements for stand-alone institutions, for integrated financial conglomerates, and for financial conglomerates that are structured as holding companies. For a given risk profile, integrated conglomerates have a lower probability of failure than either their stand-alone or decentralized equivalent. However, when risk profiles are endogenously selected, conglomeration may extend the reach of the deposit insurance safety net...