The current crisis has swept aside not only the whole of the US investment banking industry but also the consensual perception of banking risks, contagion and their implication for banking regulation. As everyone agrees now, risks where mispriced, they accumulated in neuralgic points of the financial system, and where amplified by procyclical regulation as well as by the instability and fragility of financial institutions. The use of ratings as carved in stone and lack of adequate procedure to swiftly deal with systemic institutions bankruptcy (whether too-big-to-fail, too complex to fail or too-many to fail). The current paper will not deal with the description and analysis of the crisis, already covered in other contributions to this issue will address the critical choice regulatory authorities will face. In the future regulation has to change, but it is not clear that it will change in the right direction. This may occur if regulatory authorities, possibly influenced by public opinion and political pressure, adopt an incorrect view of financial crisis prevention and management. Indeed, there are two approaches to post-crisis regulation. One is the rare event approach, whereby financial crises will occur infrequently, but are inescapable.