The latest wave of the credit crisis can be traced back to two bank failures in the US that have prompted investors fundamentally to reassess their view of the risks in the banking system.

Even though the credit crisis has dragged on for more than a year, no senior bondholder in a large financial institution had lost money until Lehman Brothers collapsed into bankruptcy last month. The Wall Street bank’s failure shocked debt investors who, until then, had mistakenly assumed that any large financial institution seen as an integral part of the financial system would not be allowed to fail.