Diversification is the traditional argument for investing internationally.
Foreign markets used to zig when U.S. stocks zagged. Today, world stock markets move together, and a severe U.S. downturn could threaten to sink everyone. In that universe are several small companies with huge potential that depend on their local economies rather than the global economy. Almost all of Denver's largest fund families have one or more international offerings. The Janus Worldwide Fund initially put Denver on the international map as manager Helen Young Hayes garnered strong returns even as foreign markets lagged.