The Influence of Anchoring and Overconfidence on Investment Decision-Making in the Saudi Stock Market: A Moderated Mediation Model

This research sheds light on the relationships between heuristic biases and investment decisions as demonstrated by Saudi investors by establishing a mediating role for investor overconfidence in the relationship between anchoring heuristics and investment decision-making. The first to present evidence for this role, the study takes into account specific types of investment decisions – i.e. decisions to buy, sell, and engage in frequent trading. Based on a sample of 598 responses, empirical evidence is presented to show that anchoring directly increases the extent to which investment decisions are irrational and also does so indirectly through its impact on overconfidence. Given that this is the case, investors would be well-advised to critically assess the influence on their investment decision-making of overconfidence, which may, in turn, be rooted in deep-seated biases such as anchoring. Further, the potential moderating effect of trading frequency on overconfidence and investment decisions is examined and a moderated mediation model presented to elucidate the relationship between anchoring bias and investment decisions. The findings underscore the importance of understanding these biases and taking a scientific approach to trading, including by engaging in infrequent trading, to producing more rational investment decisions. Put differently, the study highlights the benefit of infrequent over frequent trading: Compared to those who trade less frequently, investors who trade more frequently are more susceptible to overconfidence and anchoring biases.