What currency risk means for a UK investor
When you invest in a fund holding US, European, Japanese or global shares, you are exposed to two things at once: the performance of the underlying investments, and the movement of the exchange rate between the pound and the currencies those investments are priced in. This second factor, currency or foreign exchange (FX) risk, can significantly affect your returns even when you have no direct control over it and may not even be thinking about it.
How exchange rate movements affect your returns
Imagine you hold a fund invested entirely in US shares, priced in dollars. If the value of those shares rises by 10% in dollar terms over a year, but the pound also strengthens against the dollar by 5% over the same period, your return in pound terms will be lower than 10%, because each dollar of value is now worth fewer pounds when converted back. Conversely, if the pound weakens against the dollar while the shares rise, your return in pound terms would be boosted further than the dollar return alone suggests. This effect works in both directions and applies regardless of how the underlying companies actually perform.
Hedged versus unhedged share classes
Many funds that invest overseas offer both a "hedged" and an "unhedged" share class of the same underlying portfolio.
| Type | How it works | Effect |
|---|---|---|
| Unhedged | No attempt is made to offset currency movements; your return reflects both the underlying asset performance and exchange rate changes | More volatile in the short term due to currency swings, but simpler and usually cheaper |
| Hedged (often labelled "GBP hedged") | The fund uses financial instruments to largely offset the effect of currency movements, so returns more closely track the underlying asset's performance in its local currency | Removes most currency volatility, but incurs additional hedging costs and can behave differently during specific market conditions |
Hedged share classes are more commonly used by institutional investors, or by individuals who specifically want to isolate the performance of the underlying asset from currency swings, for example in a bond fund where currency volatility could otherwise swamp the relatively modest returns expected from the bonds themselves.
Why most long-term investors accept unhedged exposure
For most retail investors holding diversified global equity funds for the long term, such as those tracking a broad world index, unhedged exposure is generally accepted as reasonable, and often preferable, for several reasons.
- Diversification benefit. Holding assets priced in a range of different currencies is itself a form of diversification. If the pound weakens broadly, which can happen during periods of UK-specific economic difficulty, unhedged overseas holdings can act as a partial buffer, since their sterling value rises even if the underlying assets are flat.
- Lower cost and complexity. Currency hedging is not free; it involves ongoing costs that are reflected in a slightly higher charge for hedged share classes, and can also introduce its own tracking complexities.
- Currency effects tend to average out over the long term. Over long investment horizons, currency movements have historically tended to fluctuate around a broad range rather than trend consistently in one direction indefinitely, meaning the impact of currency swings on total long-term returns is often smaller than short-term volatility might suggest, though this is not guaranteed for any specific period.
Do you need to actively manage FX risk?
For most people investing through a diversified global tracker fund or multi-asset fund within an ISA or pension, actively managing currency risk is unnecessary and adds cost and complexity without a clear benefit. The exception tends to be more sophisticated investors with specific objectives, very large portfolios, or particular concerns about a specific currency pair over a defined time horizon, who may consciously choose a hedged share class for part of their portfolio. If you are simply building long-term wealth through a globally diversified portfolio, currency exposure is generally best treated as an accepted, built-in feature of overseas investing, rather than a risk requiring separate active management.
Key takeaways
- Investing overseas exposes UK investors to currency risk: exchange rate movements affect your returns independently of how the underlying investments perform.
- A strengthening pound reduces the sterling value of overseas returns; a weakening pound increases it, all else being equal.
- Hedged share classes aim to remove most currency movement from returns, at the cost of additional ongoing charges and complexity.
- Unhedged currency exposure is itself a form of diversification and is generally accepted by long-term diversified investors.
- Most retail investors in a diversified global tracker do not need to actively manage currency risk themselves.