If you’re holding primarily domestic stocks, you may not be as diversified as you think. So writes Jeffrey Kleintop, chief global investment strategist with Charles Schwab & Co., in a recent Barron’s article.

Kleintop argues that investors tend to hold mostly domestic stocks, “even when their country is the home of only a small portion of the world’s stock market,” and that an investor needs to have broad global exposure to access many different sectors of the market. Achieving this goal, he says, “has never been easier or less expensive” to do.

Increasing globalization, he says, has led to a situation where stocks correlate more closely with their international counterparts than they do with those in other sectors at home. This, he says, “has started to prompt investors to reconsider the large home bias.” While Kleintop believes that a company’s home base does matter, he notes, “it matters to all the companies in the same sector that sell or produce in that country, not just the ones headquartered there.”

While he admits that diversification can “seem to be a drag” on portfolio performance when one sector outperforms another for a chunk of time, he contends, “diversification can help lower portfolio volatility and ensure you always have some exposure to whatever sector is performing the best.”