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>

In this paper we investigate whether markets with heterogeneous network externalities can belocked-in by old technologies even if superior technologies are available. Heterogeneous networkexternalities are present when some consumers care more about the size of the market share of agood than...

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...

Strategic investors, such as corporate venture capitalists, engage in the financing of start-up firms to complement their core businesses and to facilitate the internalization of externalities. We argue that while strategic objectives make it more worthwhile for an investor to elicit high...

We illustrate the impact of detailed data in empirical economic research by considering how the increased data availability has changed the scope and focus of studies on retail gasoline pricing. We show how high-volume, high-frequency price data help to identify and explain long-term trends...

Using a comprehensive international trade data set we investigate empirical regularities (known as Zipf’s Law or the rank-size rule) for the distribution of the interaction between countries as measured by revealed comparative advantage. Using the recently developed estimator by Gabaix and...