Two bets for the price of one
When a US investor buys a Japanese stock or a German bond, they are not just betting on the asset. They are also betting on the currency. If the foreign currency falls against the dollar, your returns shrink even if the asset performed well. If the dollar weakens, you get a bonus return on top of the asset's performance.
Most investors never think about this. But it is one of the largest and least understood sources of volatility in a globally diversified portfolio. Over multi-year periods, currency moves can add or subtract several percentage points from annual returns. And unlike stock returns, currency moves have no natural upward drift. They oscillate around a mean that is impossible to predict.
The data since 2000
The numbers on inv1000.com tell the story. An index tracking developed international stocks (EFA) earned roughly 5.4% annualized in local-currency terms since 2000. In dollar terms, it earned about 4.8%, a 0.6% annual drag from a strengthening dollar. Over 25 years, that compounds into a gap of roughly 15% in final portfolio value.
Currency moves work both ways. From 2002 to 2008, the dollar weakened significantly, and US international investors earned a currency bonus of about 3% a year. The point: currency risk is large, unpredictable, and often ignored until it hurts. In 2026, with the dollar showing signs of weakening after a long run of strength, the currency tailwind may be shifting directions. No one knows when or by how much. That is precisely the problem.
Should you hedge?
Currency-hedged ETFs strip out the currency bet and leave you with pure asset exposure. But hedging costs roughly 0.02% to 0.05% per year in fund expenses, plus the implicit cost of interest-rate differentials between countries. When the dollar is strong, hedging helps. When it weakens, hedging hurts.
The practical answer: accept the currency exposure as part of the diversification package. It adds volatility, but also genuine diversification. Currencies do not move in lockstep with stocks, and a falling dollar is exactly what your portfolio needs when US assets underperform. For large international allocations, a partial hedge of around 50% offers a reasonable middle ground.
The big picture
The lesson is not to avoid international stocks. It is to understand that your return has two components, and one has nothing to do with the companies you are buying. If the dollar weakens 10% over the next five years, unhedged investors will look like geniuses. If it strengthens another 10%, they will question why they ever left home. The smart investor does not predict. They simply know it exists, account for it, and size their bets accordingly. In a world of $4,300 gold and volatile bonds, that kind of humility is worth more than any forecast.