Responses to a survey of investment management practitioners in Europe show that most practitioners are aware of key academic concepts in portfolio construction. But they still resort to ad hoc heuristics when they construct portfolios. Consideration of risk-return matters is less common in...

Many investors do not know with certainty when their portfolio will be liquidated. Should their portfolio selection be influenced by the uncertainty of exit time? In order to answer this question, we consider a suitable extension of the familiar optimal investment problem of Merton [Merton,...

In this paper, we formally show that the cross-sectional variance of stock returns is a consistent and asymptotically efficient estimator for aggregate idiosyncratic volatility. This measure has two key advantages: it is model-free and observable at any frequency. Previous approaches have used...