Calendar effect

A calendar effect is any market anomaly or economic effect which appears to be related to the calendar. Such effects include the apparently different behaviour of stock markets on different days of the week, different times of the month, and different times of year (seasonal tendencies). The term sometimes includes multi-year effects, such as the 10-year (decadal) cycle, or the 4-year U.S. presidential election cycle. It also sometimes includes time of day effects.