The current financial system is characterised by the coexistence of direct market finance, regulated banks, and shadow banks. This column looks at what gives rise to each of these sources of finance as well as the effect of bank capital regulation on the financing that flows through them. High 'flat' (or risk-insensitive) capital requirements shift intermediate-risk entrepreneurs from regulated banks to shadow banks, while high risk-based requirements do the same for high-risk entrepreneurs, increasing the risk of the corresponding loans. This result highlights the need to take into account the existence of shadow banks when designing bank capital regulation.