Prevailing wisdom in nance suggests long-run investors have a competitive advantage, since they can ride out short-run uctuations and mispricing, and pursue illiquid investments. This paper investigates if this advantage holds in a portfolio context, examining benets of international diversication across short- and longrun horizons. Employing a multi-horizon non-parametric lter, increased long-run correlations between international equity markets are detailed, even for synchronized markets. A model replicating the temporal aggregation properties of intermarket correlation is developed, indicating that short-run correlations are downward biased by frictions. Finally, the impact on portfolio allocation is investigated, demonstrating decreased risk reduction benets in the long-run.
