Investing internationally through an ETF means taking on more than just exposure to overseas companies or bonds — it usually means taking on exposure to foreign currencies as well. For a UK investor whose spending is in pounds, movements in the exchange rate can meaningfully affect returns, sometimes as much as the underlying market itself. Understanding currency hedging, and when it might or might not be considered, is an important part of building a global portfolio.
Why currency exposure exists in global ETFs
When a UK investor buys an ETF tracking, for example, the S&P 500, the fund's underlying holdings are priced in US dollars. As the fund's shares are held in sterling terms on a UK platform, the reported return an investor experiences reflects two combined effects: the performance of the underlying US shares in dollar terms, and the movement of the dollar against the pound over the same period.
An example of the combined effect
If the underlying index rises by 10% in dollar terms over a year, but the pound strengthens 5% against the dollar over the same period, the return to a UK investor holding the unhedged fund would be reduced to roughly 4.5%, since the stronger pound makes the dollar-denominated assets worth less when converted back. Conversely, a weakening pound over the same period would boost the sterling return above the underlying 10%.
What currency hedging does
A currency-hedged share class uses financial instruments, typically forward currency contracts, to offset the effect of exchange rate movements between the fund's base currency exposure and the investor's home currency (sterling, in this case). The aim is that the investor's return more closely reflects the performance of the underlying assets in their local currency, largely stripping out the currency effect, rather than eliminating market risk itself.
How the hedge is implemented
Fund managers typically roll over short-dated forward contracts on a regular basis (often monthly) to maintain the hedge, which involves a small ongoing cost, generally reflected in a slightly higher ongoing charges figure for the hedged share class compared with its unhedged equivalent.
Hedging is rarely perfect
Because hedges are typically reset periodically rather than continuously, and because the exact amount of currency exposure to hedge (given daily changes in the value of the underlying portfolio) is difficult to match perfectly, some residual "hedging slippage" or tracking difference versus a perfect hedge is normal.
Comparing hedged and unhedged share classes
| Feature | Unhedged | Currency hedged |
|---|---|---|
| Currency risk | Fully exposed to exchange rate movements | Largely offset, though not perfectly |
| Ongoing charges | Typically lower | Slightly higher, reflecting hedging costs |
| Return volatility | Can be higher or lower than underlying market, depending on currency moves | More closely tracks the underlying market's local-currency return |
| Diversification benefit | Currency moves can sometimes offset equity market moves, smoothing overall portfolio returns | Removes this potential offsetting effect |
| Complexity | Simpler to understand and hold | Adds another moving part to monitor |
Arguments some investors make for hedging
Reducing an unwanted source of volatility
For an investor who wants exposure to overseas company earnings and economic growth, but not to currency speculation as a side effect, hedging can be seen as removing an unintended and unrewarded risk, since currency movements are not necessarily correlated with long-term investment returns.
Fixed-income exposure
Currency movements can be particularly large relative to the underlying return of a bond, since bonds tend to have lower expected returns and volatility than equities. For this reason, currency hedging is used more often, and considered more frequently, in global bond ETFs than in global equity ETFs.
Arguments some investors make against hedging
Currency can act as a natural diversifier
Sterling has historically tended to weaken during periods of UK-specific economic stress, at times when global (often dollar-denominated) assets may also be under pressure for different reasons — meaning an unhedged overseas holding can sometimes cushion a portfolio during weak sterling periods, though this relationship is not guaranteed or consistent.
Added cost and complexity
Hedging is not free, and the additional charge, together with the operational complexity of the hedge itself, is a cost some investors prefer to avoid, particularly for long-term equity holdings where currency effects may average out over time.
Long time horizons
Over sufficiently long periods, currency effects have historically tended to be less significant relative to the underlying growth of company earnings, though this is a general historical pattern, not a guarantee for any specific future period.
A worked example
Suppose a hypothetical investor allocates £20,000 to a global equity ETF, split between an unhedged version and a currency-hedged version, purely for illustration. Over a hypothetical year, the underlying global index returns 8% in local currency terms, but sterling weakens by 6% against a trade-weighted basket of currencies over the same period. The unhedged holding might show a return closer to 14% in sterling terms (the market return plus the currency effect), while the hedged holding would show a return closer to the underlying 8%, minus the small additional hedging cost, perhaps landing around 7.7%. In a different year, if sterling instead strengthened by 6%, the relationship would reverse, with the unhedged holding underperforming the hedged one. This example is entirely hypothetical and illustrates the mechanism only, not a prediction of currency movements, which are inherently unpredictable.
Practical considerations when choosing
- Consider the asset class — hedging is more commonly used for bond exposure than for long-term equity exposure.
- Consider the investment horizon — very long horizons may reduce the perceived need to manage short-term currency swings.
- Compare the ongoing charges figure between hedged and unhedged versions of the same fund to understand the additional cost.
- Consider the rest of the portfolio — an investor already heavily exposed to sterling-denominated assets (UK salary, UK property) may view unhedged overseas assets as a useful additional diversifier.
Currency hedging in multi-asset and emerging market contexts
Multi-asset portfolios
Investors holding a diversified multi-asset fund often do not need to think about currency hedging directly, since many such funds already incorporate a blend of hedged and unhedged overseas exposure as part of their overall design, decided by the fund manager as part of the portfolio construction process rather than left to the individual investor.
Emerging market currencies
Hedging is considerably less common, and often more expensive or impractical, for emerging market currencies compared with major developed market currencies such as the US dollar, euro, or Japanese yen, partly reflecting lower liquidity in emerging market currency forward contracts. Most emerging market equity and bond ETFs available to UK investors are therefore unhedged by default, and currency movements in these markets can be more pronounced than in developed markets.
How to check whether a specific ETF is hedged
A currency-hedged ETF will typically carry "GBP Hedged", "Hedged", or a similar designation clearly in its name and ticker, distinguishing it from the unhedged version of the same underlying strategy. The fund's KIID/KID and factsheet will also confirm the hedging approach, alongside the specific ongoing charges figure for that share class, which is often slightly higher than the unhedged equivalent precisely because of the cost of maintaining the hedge.
The historical relationship between sterling and global equity returns
Over long periods, sterling has experienced extended periods of both strength and weakness against major currencies such as the US dollar, often linked to relative economic performance, interest rate differentials, and shifts in global investor sentiment towards UK assets specifically. Because these currency cycles have historically lasted years, sometimes even a decade or more in one direction, the choice between hedged and unhedged exposure can meaningfully affect returns over periods that many investors would consider "long term" for other purposes, even if the effect is expected to be smaller over multi-decade horizons. This history illustrates why the decision is not purely academic, even for patient, long-term investors.
A note on hedging costs relative to interest rate differentials
The cost of maintaining a currency hedge is influenced by the difference in short-term interest rates between the two currencies involved. When UK interest rates are lower than US interest rates, for example, hedging US dollar exposure back to sterling has historically tended to add a small cost (sometimes called the "carry" cost), and when the relationship reverses, hedging can occasionally provide a small benefit instead. This interest rate differential effect is a normal part of how currency forward contracts are priced, and is generally reflected automatically in the relative performance of hedged and unhedged share classes over time, without requiring any action from the investor.
Checking a platform's currency conversion charges
Separate from the question of whether an ETF share class itself is hedged, it is worth being aware that some platforms apply their own foreign exchange conversion charge when an investor buys a foreign-currency-denominated line of an ETF using sterling funds, which is a distinct, additional cost from anything related to the fund's own currency hedging policy. Comparing this platform-level conversion charge, alongside the fund's own charges, is a useful part of understanding the full cost of holding overseas exposure.
Reviewing currency exposure across an entire portfolio
Rather than assessing currency exposure fund by fund, it can be useful to periodically review the aggregate currency exposure across an entire portfolio, summing the underlying currency exposures of every unhedged overseas holding, to understand the total scale of currency risk being carried relative to the portfolio's sterling base. Some platforms and portfolio analysis tools provide this aggregated currency breakdown automatically, which can reveal a level of currency exposure larger than expected when multiple unhedged overseas funds are combined together.
Key takeaways
- Global ETFs typically carry currency exposure in addition to market exposure, which can add to or subtract from underlying returns.
- Currency-hedged share classes aim to offset exchange rate movements, usually at a slightly higher ongoing charge, and rarely with perfect precision.
- Hedging is used more commonly for global bond exposure than for global equity exposure, where currency effects relative to expected returns tend to be larger.
- Unhedged currency exposure can sometimes act as a natural diversifier, though this relationship is not guaranteed or consistent.
- The decision often comes down to asset class, time horizon, and the composition of the rest of the portfolio, rather than a universal right answer.