Debt causes fragility. When banks lack equity funding, even a small adverse shock can put the financial system at risk. Fire sales can undermine the supply of credit to healthy firms, precipitating a decline in economic activity. The failure of key institutions can threaten the payments system. Authorities naturally respond by increasing required levels of equity finance, ensuring that intermediaries can weather severe conditions without damaging others.

Readers of this blog know that we are strong supporters of higher capital requirements: if forced to pick a number, we might choose a leverage ratio requirement in the range of 15% of total exposure (see here), roughly twice recent levels for the largest U.S. banks. But as socially desirable as high levels of equity finance might be, the fact is that they are privately costly. As a result, rather than limit threats to the financial system, higher capital requirements for banks have the potential to shift risky activities beyond the regulatory perimeter into non-bank intermediaries (see, for example here).

Has the increase of capital requirements since the financial crisis pushed risk-taking beyond the regulated banking system? So far, the answer is no. However, in some jurisdictions, especially the United States, the framework for containing systemic risk arising from non-bank financial institutions remains inadequate….