Tag Archives: stock market returns

Is It Worth Betting on the ‘September Swoon’?

People have an understandable interest in patterns in stock market returns.  As we head into September, we can expect the inevitable articles about the so-called ‘September swoon.’  If you look at the period since 1926, the average return in September has been negative.  A 2011 paper in the Journal of Applied Finance concluded that the historical occurrence of negative returns for the stock market in September is so strong and consistent that it cannot easily be explained away.  There are a range of other so-called ‘calendar effects’ in which a specific time of the year, month, or week has historically delivered returns that are markedly different from the average across all periods.  There are no conclusive explanations for these effects and, in a rational world, these types of anomalies should not persist—but they do.  If they expect stock prices to decline in September, savvy speculators should start to sell in August in anticipation of this drop and this selling should dilute the eventual drop in September.  Over time, this type of effect should, in theory, disappear to investor anticipatory buying or selling.  Nonetheless, these effects remain prominent in historical stock prices. Continue reading