In this paper we study the equilibrium in a heterogeneous economy with two groups of investors. Over-confident experts incorrectly assume that their signal for the drift of the dividend process is correlated with the true drift, but interpret the signal otherwise perfectly. Rational laymen avoid...

Model mis-specification can cause substantial utility losses in portfolio planning. In this paper, we compare two approaches to cope with this problem, robust control and learning. We derive the optimal portfolio strategies and the utility losses due to model mis-specification. Surprisingly,...

Model mis-specification can cause substantial utility losses in portfolio planning. In this paper, we compare two approaches to cope with this problem, robust control and learning. We derive the optimal portfolio strategies and the utility losses due to model mis-specification. Surprisingly,...

Tests for the existence and the sign of the volatility risk premium are often based on expected option hedging errors. When the hedge is performed under the ideal conditions of continuous trading and correct model specification, the sign of the premium is the same as the sign of the mean hedging...

This paper deals with the superhedging of derivatives on incomplete markets, i.e. with portfolio strategies which generate payoffs at least as high as that of a given contingent claim. The simplest solution to this problem is in many cases a static superhedge, i.e. a buy-and-hold strategy...