Do Election Results Predict Equity Market Performance?

February 24, 2016

During election seasons we are frequently asked about what will happen to the market if a particular candidate or party wins, or whether certain years of the presidential cycle are better for investors. While there are numerous opinions about how differing public policies can affect the economy and financial markets — which goes well beyond the scope of this Chart of the Week — we can observe some trends from history. Since 1926, the first year of a presidential term on average is the weakest, while the third year generally performs well. The election year itself tends to be fairly average. Additionally, the market has generally performed better while a Democrat was sitting president, with an average return of 15% compared to 8.6% for Republican presidents.

While these trends seem interesting, it would be imprudent to make any market predictions based on this data. The historical data is extremely limited and undoubtedly a case of random patterns in a small data set rather than a legitimate correlation. For instance, an investor who only invested in the stock market when the NFC won the super bowl would significantly outperform one that invested when the AFC won (14.6% compared to 8.2%). Similar results can also be seen when investing in only odd years, or years that end with a certain digit (3, 5, etc). In order to be statistically significant, one would need over 2,000 election year data points to achieve a meaningful significance level. While there may or may not be particular reasons behind these realized returns patterns, from a statistical standpoint it would be unwise to base any investment decisions off of them.