Portfolio diversification: the influence of herding,status-quo bias,and the gambler’s fallacy

This experimental study examines the influence of herding following the majority of fellow gamblers or the most successful gambler (guru)], status-quo bias, and the gambler’s fallacy on diversification behavior. We find that neither herding nor status-quo bias contributes significantly to non-optimal portfolio choices. The gambler’s fallacy, however, plays an important role in these decisions. Many subjects appear to find patterns in a history of random events and then use these “patterns” to infer the sequence of future events. The gambler’s fallacy is significantly responsible for the fact that the optimal structure of a portfolio is considered in only 37.7% of all choices made by an investor.