Undiversified - or stock picking - portfolios may dominate well diversified benchmarks, when these benchmarks are not mean-variance efficient. Starting from Markowitz's Modern Portfolio Theory we derive simple (linear regression) tests to separate stock picking from diversification. Over 60% of...

We investigate two alternative explanations why men may hold more stocks than women. Apart from a gender difference in risk aversion, gender differences in either optimism or in perceived risk of financial markets might cause men to hold more risky assets. Our results show that men tend to be...

We study the relative importance of social factors (including household, workplace, and neighbourhood peer effects) and personal characteristics (including age, gender, tax rates, and funds under management) for asset allocation decisions. The most important factors (in order) are household peer...

Markowitz's mean-variance portfolio optimization is either inefficient or impossible when the number of assets becomes relatively large. To overcome this difficulty, we propose several component-wise boosting learning methods that, in a linear regression specification, can iteratively select the...