Average returns for small firm size portfolios tend to decrease during the week in January, with Monday returns highest and Friday lowest. More striking are the results after controlling for Mondays and Fridays in the first and the last 3 weeks of January. Monday returns in this first week are...

One of the widely discussed issues in the financial literature is the daily seasonality in asset prices. In this study, we shed fresh lights and explore the evolution of weekday seasonality in the US capital market. For this sake, we utilize daily data for the period January 1990 to August 2022....