
I thought you might be interested in a new research which looks at the impact of presidential elections on the US stock market. Presidential Election Uncertainty and Common Stock Returns in the United States, written by
Jeffrey Born, a professor of finance at Northeastern University’s business school, provides evidence that the most important factor in an election’s impact is the certainty of the outcome. In other words, the tighter the race, the more volatile the market.
Below is an abstract of the research piece. You can find Prof. Born’s bio here:
http://cba.neu.edu/faculty/directory_detail.cfm?e=138. Please let me know if you’d like to read a draft of the entire report, or if you’d like to speak to Prof. Born.
There is substantial evidence on the existence of a political business cycle. Studies demonstrate marked differences in the policy choices of the two major political parties in the United States. These policy differences are associated with significant differences in macro-economic outcomes and performance. The influence of macro-economic forces on common stock returns is well documented in the finance literature. This suggests the following linkage: political change produces policy change, which produces different macroeconomic outcomes, which should impact the distribution of common stock returns.
In an efficient market, the expectation of, or uncertainty about, political change should be incorporated into share prices. Prior research into the influence of political change has frequently been flawed by the assumption that the outcome of the election is known a priori. Furthermore, prior studies failed to control for the possibility of serial correlation in daily common stock returns, which has the potential to bias test statistics. We incorporate the uncertainty of a presidential election's outcome into our analysis of pre-election returns in the United States through the use of candidate preference (i.e., polling) data. Standardizing the difference in the two leading candidate's preference percentage by the sampling error of the poll produces a measure of electoral outcome uncertainty. We find that political uncertainty does impact aggregated common stock returns during the presidential election cycle.
If the candidate of the incumbent political party (who could be standing for re-election) does not enjoy a significant lead in the polls, stock market volatility rises. Not surprisingly, as total risk rises, mean returns rise. However, if the candidate of the incumbent political party moves to (or opens with) a commanding lead in the polls, the possibility of political change diminishes, as does volatility and mean daily returns.