As human beings we have a deep-seated desire to explain natural and social phenomena. We have an in-built search mechanism which looks for causation in order to explain the world around us. For example, the US stock market declined on the day after Obama's election. Why? Most people connected the two events, but the two may have been totally unrelated. Another example can be found in today's Metro where it is claimed that crime falls and birth rates go up in Mexico City whenever Javier Hernandez is playing for Manchester United. These may simply be crude correlations and there may be no causation whatsoever. It requires rigorous statistical testing to demonstrate correlation never mind causation!
Daron Acemoglu, Simon Johnson, Amir Kermani, James Kwak and Todd Mitton have written a paper on whether firms connected to Timothy Geithner benefited from these connections. They do so by looking at how stocks of these firms reacted to the announcement that he was a nominee for Treasury Secretary in November 2008. They find that there were large abnormal returns for connected firms. Below is the paper's abstract and the full paper is available here . The announcement of Timothy Geithner as nominee for Treasury Secretary in November 2008 produced a cumulative abnormal return for financial firms with which he had a connection. This return was about 6% after the first full day of trading and about 12% after ten trading days. There were subsequently abnormal negative returns for connected firms when news broke that Geithner's confirmation might be derailed by tax issues. Excess returns for connected firms may reflect the perceived impact of relying on the advice of a small ne...