In recent years, the outperformance of their domestic markets relative to international markets has prompted U.S. and European investors to question the wisdom of global investing. Despite the superior risk-adjusted returns of U.S. equities and high correlations with other developed markets in recent years, investors should resist the urge of purging non-U.S. equities from their portfolios. Over a long-term, perpetual horizon, we would expect developed markets equities to experience similar performance.  Investing across borders provides the benefits of nearly doubling the available opportunity set, while also reducing the variability of returns over the long term.