Temporal Aggregation Effects on the Construction of Portfolios of Stocks or Mutual Funds through Optimization Techniques - Some Empirical and Monte Carlo Results

In this paper we test the effects of temporal aggregation (disaggregation) on the efficiency of portfolio construction using the mean variance optimization approach. Using Monte Carlo techniques and empirical data from the Athens Stocks Exchange we confirm that the use of temporally aggregated data effects very seriously the efficiency of the constructed portfolio. Especially as the degree of temporal aggregation increases the application of optimization techniques could lead to different results regarding the percentage of stocks participation, the weights and finally the total portfolio performance.Portfolio Optimization, Stocks; Temporal Aggregation; Stochastic Simulation, The Banking Sector of the Athens Stocks Exchange

Optimal Portfolio Analysis for the Czech Republic, Hungary and Poland During 2001– 2006 Period

This paper examines the strategy of investing in selected East European stock markets: The Czech Republic, Hungary, and Poland. These stocks markets are representative of the emerging stock markets of Eastern Europe and examined from the perspective of an investor who invests solely in the Eastern European markets. International Portfolio investment gradually increased during the late 2000’s in this region. Four portfolio construction techniques were used including the Markowitz mean-variance analysis. The optimal portfolios are evaluated using standard selection criteria and it is shown that possessing a diversified international portfolio which includes some of the aforementioned stock markets is beneficial.Portfolio diversification; Markowitz Mean Variance Frontier; Eastern European Countries.

A Note on the Diachronic Behaviour of the OECD Forecasts for Greece

In this short paper a Gamma distributed lags model is used to study the diachronic responses between the actual data and the forecasts supplied by OECD the last 27 years for the case of the Greek Economy. According to our results we verified the potentials of the OECD to improve its forecasts as the size of the foreseeable period decreases. Irrespective of how good are the OECD’s forecasts, there is certainly much room for further improvement.OECD Forecasting Accuracy, Greek Economy, Gamma Distributed Lags Model