Bubbles and crashes are an endemic feature of financial markets in capitalist countries. Thus, as a result of deregulation, the balance sheets of universal banks became fully exposed to these bubbles and crashes, undermining the stability of the banking system. The Basel approach to stabilise the banking system has as an implicit assumption that financial markets are efficient, allowing us to model the risks universal banks take and to compute the required capital ratios that will minimise this risk. I argue that this approach is unworkable because the risks that matter for universal banks are tail risks, associated with bubbles and crashes. These cannot be quantified. As a result, there is only one way out, and that is to return to narrow banking, a model that emerged after the previous large-scale banking crisis of the 1930s but that was discarded during the 1980s and 1990s under the influence of the efficient market paradigm.
Paul De Grauwe is Professor of Economics at the University of Leuven and Associate Senior Fellow at CEPS.