Since the outbreak of the subprime crisis in mid 2007, the world’s financial markets have suffered unprecedented turmoil. Many banks, even large institutions that had previously been considered icons of stability, failed or had to be rescued or nationalised by their governments. The financial crisis has prompted regulators in the US and Europe to reexamine how much capital is enough capital for banks. Regulators generally agree that banks were too highly leveraged and that, in the future, banks should be required to have more capital. Discussion has turned to contingent capital (another form of hybrid capital) as a necessary component of capital going forward.