We investigate what it means for one act to be more ambiguous than another. The question is evidently analogous to asking what makes one prospect riskier than another, but beliefs are neither objective nor representable by a unique probability. Our starting point is an abstract class of...

Optimal portfolio rules are derived under uncertainty aversion by formulating the portfolio choice problem as a robust control problem. The robust portfolio rule indicates that the total holdings of risky assets as a proportion of the investor's wealth could increase as compared to the holdings...

The paper shows that financial market equilibria need not exist if agents possess cumulative prospect theory preferences with piecewise-power value functions. The reason is an infiniteshort-selling problem. But even when a short-sell constraint is added, non-existence can occur due to...

Most decisions concerning (self-)insurance and self-protection have to be taken in situations in which a) the effort exerted precedes the moment uncertainty realises, and b) the probabilities of future states of the world are not perfectly known. By integrating these two characteristics in a...

In 1997, France Telecom, the state-owned French telephone company, went through a partial privatization. We adapt a standard neoclassical model to predict how employees might respond to the firm's offer to sell them various classes of shares. Using a database that tracks over 200,000 eligible...

We address the problem of choosing a portfolio of policies under "deep uncertainty." We introduce the idea of belief dominance as a way to derive a set of non-dominated portfolios and robust individual alternatives. Our approach departs from the tradition of providing a single recommended...

This paper analyzes whether, and to what extent, the Danish 1, 5 and 10-year equity premia are predictable. We examine the predictive power of a comprehensive list of financial ratios, interest rates and so forth. The results show that the 5-year premium is predictable in the sense that the...

This contribution starts out by noting a conflict of interest between consumers and insurers. Consumers face positive correlation in their assets (health, wealth, wisdom, i.e. skills), causing them to demand a great deal of insurance coverage. Insurers on the other hand eschew positively...

This study applies financial portfolio theory to determine efficient electricity-generating technology portfolios for the United States and Switzerland, adopting an investor point of view. Expected returns are defined by the rate of decrease of power generation cost (with external costs...

This study uses Markowitz mean-variance portfolio theory with forecasted data for the years 2005 to 2035 to determine efficient electricity generating technology mixes for Switzerland. The SURE procedure has been applied to filter out the systematic components of the covariance matrix. Results...