Household investment mistakes are an important concern for researchers and policymakers alike; portfolio underdiversification ranks among those mistakes that are potentially most costly. However, its roots and empirical importance are poorly understood. I estimate quantitatively meaningful...

This paper examines the relationship between overconfidence and losses from under-diversification among Dutch investors. We find that a lack of proper portfolio diversification is positively associated with overconfidence. Part of this relationship is mediated through the lower propensity of...

Economic theory suggests that households should invest their financial wealth in a combination of cash and a well-diversified equity portfolio. Yet, many households' equity investments are strongly concentrated in a few assets. Attempts to explain this discrepancy have included low levels of...