Cross-Border Diversification in Bank Asset Portfolios

We compute optimally diversified international asset portfolios for banks located in France, Germany, Italy, the United Kingdom and the United States using the mean-variance portfolio model with currency hedging. We compare these benchmark portfolios with the actual cross-border asset positions of banks from 1995 to 2003 and ask whether the differences are best explained by regulations, institutions, cultural conditions or other financial frictions. Our results suggest that both culture and regulations affect the probability of a country's being overweighted in banks' portfolios: countries whose residents score higher on a survey measure of trust are more likely to be overweighted, while countries that have tighter capital controls are less likely to be overweighted. From a policy standpoint, the importance of culture suggests a limit to the degree of financial integration that may be achievable by the removal of formal economic barriers.