Stock Lingo, The Calender Effect
I enjoy this stock lingo because it reminds me of a wide assortment of conspiracy theories and the like. If you ever used to watch the X-files, you know what I am talking about!
The Calender effect simply is a collection of theories that say certain months, days, or times of the year are more volatile than others. That during these certain times the stock market will always fall or always rise, etc.
The most well known is the October Effect, with others being the Monday effect, the Halloween effect, and the January effect. Now, it really depends on who you are talking to when it comes to proving any of these theories correct, because though there is SLIGHT statistical evidence to prove the existence of these calender effects, nothing is clear cut in stone.
With the October effect for example, if you look back in stock market history, some of the greatest crashes occured during this month. The crash of 1929 and 1987 are two big ones. But these are just two Octobers out of 80+, so many will write this off. The psychological effect though still is evident amongst many traders who are extra catious during this month.
Add October 13th, 2 years after the meltdown in 87. This one is also known as the minicrash.