Economics Insights @ CBS

This paper develops efficient methods for computing portfolio value-at-risk (VAR) when the underlying risk factors have a heavy-tailed distribution. In modeling heavy tails, we focus on multivariate t distributions and some extensions thereof. We develop two methods for VAR calculation that exploit a quadratic approximation to the portfolio loss, such as the delta-gamma approximation. In the first method, we derive the characteristic function of the quadratic approximation and then use numerical transform inversion to approximate the portfolio loss distribution.

Two studies were conducted among professional security analysts to explore their patterns of decision making while managing investment portfolios. In study 1, a computer-based simulation, the analysts' styles differed markedly, with most exhibiting either a momentum or contrarian approach, as indicated by responses to portfolio stock price changes. Study 2 used a verbal protocol procedure and semistructured depth interviews to probe the analysts' thought processes.

This research examines the effects of lying about one's attitudes (attitude dissimulation) on various strength-related consequences for weakly held attitudes. Dissimulation for weak attitudes could either produce a strengthening effect on the underlying attitude (if lying involves activation of the true attitude) or a weakening effect (if lying sets up a competing link to the false attitude). Results from three experiments using different dissimulation paradigms support the strengthening hypothesis.

The authors discuss research progress and future opportunities for modeling consumer choice on the Internet using clickstream data (the electronic records of Internet usage recorded by company web servers and syndicated data services). The authors compare the nature of Internet choice (as captured by clickstream data) with supermarket choice (as captured by UPC scanner panel data), highlighting the differences relevant to choice modelers.