Individual investors and the Monday effect
Authors: B.C. Bishal , Wang Weiwei , Gurun Ayfer , Cready William 
Published: September 2019

Purpose
For this study, the authors document day-of-the-week trading patterns of individual investors using a unique data set of NYSE-listed firms and discuss their influence on the Monday effect. It is found that Monday stock returns are generally lower than those of other weekdays and, on average, negative. Unlike previous researchers, the authors use actual trading data for individual investors rather than proxies to measure individual investor activity, such as the percentage of odd-lot trading. The results demonstrate that the trading activity of individual investors on Mondays is lower than previously documented. This finding contradicts the long-held belief that individual investors are most active on Mondays. In addition, the authors find that individual investors’ trading activity during the week broadly follows corporate announcement patterns. The least amount of firm-specific information is released on Friday, followed by Monday, Tuesday, Thursday and Wednesday. Accordingly, individual investors trade the least number of shares on Friday, followed by Monday, Tuesday, Thursday and Wednesday, strengthening the argument that individual investors trade on attention-grabbing stocks. Taken together, the authors’ findings challenge those of previous studies that hold individual investors responsible for the Monday effect. The paper aims to discuss this issue.

Design/methodology/approach
The authors use actual trading data for individual investors rather than proxies to measure individual investor activity, such as the percentage of odd-lot trading, to study the existence of Monday effect in stock prices.

Findings
The results show that the trading activity of individual investors on Mondays is lower than previously documented. This finding contradicts the long-held belief that individual investors are most active on Mondays. In addition, the authors find that individual investors’ trading activity during the week broadly follows corporate announcement patterns.

Research limitations/implications
The authors find that individual investors’ trading activity during the week broadly follows corporate announcement patterns. The least amount of firm-specific information is released on Friday, followed by Monday. Accordingly, individual investors trade the least number of shares on Friday, followed by Monday, strengthening the argument that individual investors trade on attention-grabbing stocks. Taken together, the authors’ findings challenge those of previous studies that hold individual investors responsible for the Monday effect.

Practical implications
Financial advisors.

Originality/value
The authors find that individual investors’ trading activity during the week broadly follows corporate announcement patterns. The authors challenge the commonly hold view that individuals often make trading decisions during weekends and thus trade on Mondays, and find that the least amount of firm-specific information is released on Friday, followed by Monday. Accordingly, individual investors trade the least number of shares on Friday, followed by Monday. Taken together, the authors’ findings challenge those of previous studies that hold individual investors responsible for the Monday effect.