This introductory article examines the role of capital in financial institutions — why it is important, how market-generated capital ‘requiremenents’ differ from regulatory requirments and the form that regulatory requirements should take. Along the way, we examine historical trends in bank capital, problems in measuring capital, and some possible unintended consequences of capital requirements. Within this framework, we evaluate how the contributions to this special issue advance the literature and suggest topics for future research.

We show how a high degree of commonality in investor liquidity shocks can diminish incentives for intermediaries to keep markets open and lead to market collapse, even without information asymmetry or news affecting fundamentals. We motivate our model using the perpetual floating-rate note market where two years of explosive growth – in which issues by high quality borrowers were placed with institutional investors and traded in a liquid secondary market – were followed by a precipitous collapse when market intermediaries withdrew due to large order imbalances. We shed new light on the trade-off between ownership concentration and market liquidity.