Detecting and Explaining Systemic Risks of US Mortgage Banks - Evidence from the Subprime Crisis

In recent history, financial markets worldwide experienced severe turmoil due to the subprime crisis originating from the practice of US mortgage banks to securitise loans given especially to subprime borrowers. In the same crisis, several distressed banks were bailed out by states with even more banks receiving financial aids from governments. Using a unique data sample of 100 announcements of US mortgage banks between 2006 and 2009, this paper provides em-pirical evidence that isolated failures of US mortgage banks caused significant contagion effects in the US financial system. Conversely, especially the bailouts of Fannie Mae and Freddie Mac led to significant positive valuation effects at rival banks. In the cross-sectional analyses, contrary to previous studies in the literature on past financial crises, we find evi-dence for pure contagion effects following mortgage bank failures and rational valuation effects following bailouts. These results indicate that several of the failures of US mortgage banks during the subprime crisis caused irrational contagion in the US financial system thus justifying government intervention