Transition to the Euro and its impact on country portfolio diversification

By examining the impact of the introduction of the Euro on stock markets and on country diversification within the Eurozone, the evidence does not suggest a high risk to the stock market to justify a risk premium as a result of currency union. Although the Euro market integration has increased inter-country correlations, it does not preclude gains from international diversification, which partially rely on the non-Eurozone countries for an optimal portfolio in a mean-variance framework. Furthermore, the empirical evidence supports that there is a significant stationarity of average correlations over time between pre-Euro and post-Euro periods, and it has improved since the introduction of the Euro. Also, results show that the Euro produced a change in volatility with a different pace within the Eurozone vis-à-vis non-Eurozone countries, to support a direct and opposite relationship between volatility and correlation.Euro International diversification Volatility Serial correlation stability European stock markets Prospects of the Euro Benefits of monetary union

Portfolio selection subject to experts' judgments

Since Markowitz [Markowitz, H. M. (1952). Portfolio selection. The Journal of Finance, 7, 77-91.], mean-variance theory has assumed that risky-asset returns to be random variables. The theory deals with this uncertainty by further assuming that investors hold homogeneous beliefs regarding the probability distribution governing return uncertainty. While the theory deals with return uncertainty, it fails to address measurement imprecision. In his original work, Markowitz recognized the need to combine randomness with heterogeneous expert judgment resulting in such imprecision. The main objective contributions of the paper are (i) to explore the implications of fuzzy return indeterminacy on mean-variance optimal portfolio choice, (ii) to use bid-ask spread as a proxy measure of the indeterminacy or "fuzzy" nature of random returns, and (iii) to introduce a brief, self-contained glimpse of empirical representations to practitioners unfamiliar with the fuzzy modeling field. Exposition, such as this one, is expected to open new collaborations between other branches of fuzzy mathematics and asset-pricing theories.Portfolio selection Fuzzy-set theory Mean-variance theory Subjective measures Ambiguity-aversion Experts' judgments