Spatial concentration and plant-level productivity in France

This paper analyzes empirically the effect of spatial agglomeration of activities on plant-level productivity, using French firm and plant-level data from 1996 to 2004. We exploit short-run variations of variables by making use of GMM estimation. This allows us to control for endogeneity biases that the estimation of agglomeration economies typically encounters. This means that our paper focuses on a subset of agglomeration economies, the short-run ones. Our results show that French plants benefit from localization economies, but we find very little - if any - evidence of urbanization economies. We also show that those localization benefits are relatively well internalized by firms in their location choice: we find very little difference between the geography that would maximize productivity gains in the short-run and the geography actually observed.     

Spurious regressions in technical trading

This paper investigates the spurious effect in forecasting asset returns when signals from technical trading rules are used as predictors. Against economic intuition, the simulation result shows that, even if past information has no predictive power, buy or sell signals based on the difference between the short-period and long-period moving averages of past asset prices can be statistically significant when the forecast horizon is relatively long. The theoretical analysis reveals that both ‘momentum’ and ‘contrarian’ strategies can be falsely supported, while the probability of obtaining each result depends on the type of the test statistics employed.     

What makes Islamic banks different? A multivariate approach

Using data from 8615 banks (including 123 Islamic banks) in 124 developed and developing countries for the period between 2006 and 2012, we examine the financial characteristics that distinguish between conventional and Islamic banks. As banks’ financial characteristics are multi-faceted concepts, our indicators are constructed using principal component analysis. We find that Islamic banks are more capitalized, more liquid and more profitable, but have more volatile earnings compared to US and European banks. However, similarities in terms of liquidity and earnings volatility are more noticeable when the sample is limited to banks operating in countries where both systems coexist. Finally, we find that higher capital makes the returns of Islamic banks more volatile, while higher liquidity decreases the profitability of conventional banks.     

Does ethics improve stock market resilience in times of instability?

This paper compares the resilience of ethical (Islamic and socially responsible) indexes among five developed (US, UK, Japan, Canada, Australia) and three emerging markets (Brazil, India, South Africa) during the period following the 2008 subprime crisis. It relies on a multivariate CAPM-EGARCH model that accounts for sudden changes in volatility through the application of an iterated cumulative sums of squares (ICSS) algorithm on daily data over the sample period 2008–2014 to model time-varying volatility and ensure reliable estimates. The study confirms the lower systemic risk associated with Islamic indexes during the bearish period and reports that SRI, despite being more subject to systemic risk, offered higher alphas in highly integrated markets, while Islamic indexes performed better in less integrated ones. The evidence also reveals a very limited increase in the models’ predictability power from the integration of sudden changes in volatility into the EGARCH models during the full sample period. This limit is more marked during the bearish sub-period. Our findings have important implications for international investment and portfolio diversification perspectives in times of financial downturn.