Werktageffekte

Werktageffekte, also known as business day effects or calendar effects, refer to observable patterns in financial markets or economic data that occur on specific days of the week. These effects suggest that trading activity, price movements, or economic indicators are not randomly distributed throughout the week but rather exhibit regular fluctuations. A common example is the "Monday effect," where stock market returns on Mondays are historically lower than on other days, sometimes attributed to the aggregation of negative news over the weekend or the timing of institutional trading. Conversely, some studies have observed a "Friday effect," with potentially positive returns as investors position themselves for the weekend. Other days of the week can also show distinct patterns, though often less pronounced or consistent. The precise causes of werktageffekte are debated and can include behavioral biases of investors, institutional trading strategies, the timing of economic data releases, or the settlement procedures of financial instruments. While these effects can be statistically significant, their practical exploitability for consistent profit is often limited due to transaction costs and the tendency for such patterns to diminish as they become widely known and exploited.