International Investing: How Much Overseas Exposure Do You Need?

American investors are famously biased toward American stocks. The average US investor holds over 80% of their equity portfolio at home — despite the US making up roughly 60% of global market value. That gap is called home bias, and it's usually a mistake.

The Case for Owning International Stocks

Global markets are not synchronized. There are entire decades where international stocks outperform the US — most recently in the 2000s, when US stocks lost money for a full decade while emerging markets and developed international markets delivered solid returns.

Owning overseas stocks means:

• Diversification. You're no longer betting your entire retirement on one country's economy and one market's valuation.
• Cheaper valuations, sometimes. When US stocks are expensive relative to earnings, international markets are often cheaper.
• Currency exposure. A weakening dollar boosts the returns of foreign holdings.

The Case Against (and the Real Costs)

International investing isn't free money. There are real tradeoffs:

• Currency risk. A strengthening dollar can wipe out foreign gains in dollar terms.
• Higher costs and taxes. International funds are slightly more expensive, and foreign dividend withholding taxes can drag returns in taxable accounts.
• Different regulatory and accounting regimes in emerging markets mean more tail risk.

How Much Should You Own?

There's no single right answer, but here are defensible positions:

• Global market-cap weighting (roughly 35–40% international): the pure diversification answer. Vanguard and others use this as their default.
• 20–30% international: the mainstream sweet spot. Most target-date funds land here.
• 0–10% international: defensible only if you explicitly believe US outperformance will persist — which is a bet, not a default.

The mistake isn't a specific number; it's never making the decision at all, or flip-flopping based on which region performed best last year.

How to Own It

One low-cost total international index fund covers developed and emerging markets in a single holding. Add it alongside your US index fund and you've built the global stock core of a portfolio without complexity. See how to build a portfolio and diversification explained to put it together.

The Bottom Line

Your future spending is global — your investments should be too. Own enough international exposure that a lost decade in the US doesn't sink your plan, but not so much that currency swings and costs eat the diversification benefit.