For a long list of investment “biases,” including lack of diversification, excessive trading, and the disposition effect, we find that genetic differences explain up to 45% of the remaining variation across individual investors, after controlling for observable individual characteristics. The evidence is consistent with a view that investment biases are manifestations of innate and evolutionary ancient features of human behavior. We find that work experience with finance reduces genetic predispositions to investment biases. Finally, we find that even genetically identical investors, who grew up in the same family environment, often differ substantially in their investment behaviors due to individual-specific experiences or events.

Analyzing the savings behavior of a large sample of identical and fraternal twins, we find that genetic differences explain about 33 percent of the variation in savings propensities across individuals. Individuals are born with a persistent genetic predisposition to a specific savings behavior. Parenting contributes to the variation in savings rates among younger individuals, but its effect decays over time. The environment when growing up (e.g., parents’ wealth) moderates genetic effects. Finally, savings behavior is genetically correlated with income growth, smoking, and obesity, suggesting that the genetic component of savings behavior reflects genetic variation in time preferences or self-control.

Existing evidence suggests that the Sarbanes–Oxley Act (SOX) may be beneficial to US investors, but that foreign firms are perhaps less likely to list in the USA after SOX. This raises the question of whether foreign firms avoid listing in the USA after SOX because the Act imposes unnecessary costs upon firms. The objective of this article is to reconcile the US and international evidence by distinguishing between the effect of SOX on controlling shareholders and managers of foreign firms and the effect on minority investors of these firms. Our results suggest that insiders of foreign firms believe that the regulation makes the extraction of value from minority investors more difficult and costly for them. Outside investors in foreign firms, on the other hand, seem on average to believe that SOX is beneficial to them. The combination of these results reconciles the existing US and international evidence regarding SOX.

We find that several factors explain an individual investor׳s style, i.e., the value versus growth orientation of the investor׳s stock portfolio. First, we find that an investor׳s style has a biological basis and is partially ingrained in an investor from birth. Second, we show that an investor׳s hedging demands as well as behavioral biases explain investment style. Finally, an investor׳s style is explained by life course theory in that experiences, both earlier and later in life, are related to investment style. Investors with adverse macroeconomic experiences (e.g., growing up during the Great Depression or entering the labor market during an economic recession) or who grow up in a lower socioeconomic status rearing environment have a stronger value orientation several decades later. Our research contributes a new perspective to the long-standing value and growth debate in finance.