Actual portfolios contain fewer stocks than are implied by standard financial analysis that balances the costs of diversification against the benefits in terms of the standard deviation of the returns. Suppose a safety first investor cares about downside risk and recognizes the heavytail feature...

See the article in the <I>Annals of Financial Economics</I> (2013). Volume 8, issue 2, pages 1-18.<P> In this paper, we develop a modified maximum likelihood (MML) estimator for the multiple linear regression model with underlying student t distribution. We obtain the closed form of the estimators, derive...</p></i>

Risk managers use portfolios to diversify away the unpriced risk of individual securities. In this article we compare the benefits of portfolio diversification for downside risk in case returns are normally distributed with the case of fat-tailed distributed returns. The downside risk of a...

This discussion paper led to a publication in <I>Economics Letters</I> (2014). Vol. 123(3), pages 291-294.<P> Hausman (1978) developed a widely-used model specification test that has passed the test of time. The test is based on two estimators, one being consistent under the null hypothesis but...</p></i>

This paper studies an intermediated market operated by middlemen with high inventory holdings. I present a directed search model in which middlemen are less likely to experience a stockout because they have the advantage of inventory capacity, relative to other sellers. The model explains why...

In its landmark ruling in Illinois Brick Co. v. Illinois in 1977, the U.S. Supreme Court restricted standing to sue for recovery of antitrust damages to direct purchasers. However, antitrust damages are typically (in part) passed on to intermediaries lower in the chain of production and...

This paper presents a model of second-degree price discrimination and inter-group effects to describe the full-service pricing behaviour in the passenger aviation market. Consumer heterogeneity is assumed on both a horizontal and a vertical dimension, while various distinct market structures,...

This paper analyzes the relative economic power position of home carriers in hub-and-spoke systems. Hub-and-spoke systems may lower costs on densely traveled routes and enable economically viable operations on less densely traveled routes. The reverse side is probably that carriers enjoy...

This discussion paper led to an article in 'Journal of Economic Theory' (2014). Volume 150, pp. 778-814.<P> We propose behavioral learning equilibria as a plausible explanation of coordination of individual expectations and aggregate phenomena such as excess volatility in stock prices and high...</p>