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 discussion paper resulted in a publication in the <A href="http://onlinelibrary.wiley.com/doi/10.1111/j.1468-0351.2011.00425.x/abstract;jsessionid=F64011DF99B22B6E2BF33FDA1C47DE9C.f04t03">'Economics of Transition'</A>, 2011, 19(4), 639-666.<P> Whether fiscal policy is sustainable depends on a government's future revenue and expenditure streams, both of which are highly uncertain. In commodity-rich countries, this problem is...</p></a>

This discussion paper resulted in an article in the <I>Journal of the American Statistical Association</I> (2007). Vol. 102, issue 477, pages 16-27.<p> Novel periodic extensions of dynamic long memory regression models with autoregressive conditional heteroskedastic errors are considered for the analysis...</p></i>

This discussion paper led to a publication in the <I>Electronic Journal of Statistics</I> (2014). Vol. 8, pages 1088-1112.<P> We characterize the dynamic properties of Generalized Autoregressive Score (GAS) processes by identifying regions of the parameter space that imply stationarity and ergodicity. We...</p></i>