Currency Hedging Strategies for International Investors: When to Hedge and When Not To

Currency movements are a permanent feature of internationally mobile life. For an investor whose assets are predominantly in GBP and whose retirement will be spent in EUR, a 10% weakening of sterling represents a 10% reduction in purchasing power — the equivalent of a significant bear market in portfolio terms.

Yet hedging this currency risk has a cost. Sometimes the cost is trivial; sometimes it materially exceeds the likely benefit. Understanding when hedging makes financial sense — and when it is an unnecessary drag on returns — is one of the more technically demanding aspects of international investment planning.

This guide explains the mechanics of currency hedging, the main instruments available, the empirical evidence on long-term currency effects, and a practical framework for deciding how much hedging makes sense for an internationally mobile investor.

What Currency Hedging Is and How It Works

Currency hedging means taking a financial position that offsets the currency risk embedded in another position. If you hold USD assets and are concerned that the USD will weaken against GBP (reducing the GBP value of your USD assets), you can take a position that profits if USD weakens — offsetting the loss on the underlying assets.

The simplest hedging instruments:

Forward contracts: an agreement to exchange a fixed amount of one currency for another at a specified rate on a specified future date. If you know you will need €200,000 in six months (to complete a property purchase), you can buy euros forward today at today's rate. The bank holds a deposit (typically 5-10% of the contract value), and you receive certainty on your euro cost in sterling terms.

Forward contracts are available from banks and specialist currency brokers (OFX, Moneycorp, Currencies Direct). They eliminate exchange rate uncertainty for known future obligations — property completions, school fee payments, large transfers.

Currency options: the right (but not obligation) to exchange currency at a specified rate on or before a specified date. More flexible than forward contracts (you can let the option lapse if rates move in your favour) but more expensive (you pay a premium for the option). Used by large corporates and sophisticated investors; less commonly used by private individuals due to cost and complexity.

Currency ETF hedges: some ETFs offer hedged share classes that remove the currency return from the investment. A GBP-hedged version of a US equity ETF delivers the USD equity return translated to GBP at a fixed rate — the currency movement between USD and GBP is neutralised. Discussed in more detail below.

The Cost of Hedging: Interest Rate Differentials

Currency hedging is not free. The cost of a forward contract is determined primarily by the interest rate differential between the two currencies involved.

If UK interest rates are 4% and US interest rates are 5%, a UK investor buying USD forward will effectively "pay" the 1% differential in the form of a less favourable forward rate than the current spot rate. This is not profit or loss to the bank — it is the mathematical expression of the interest rate differential; the "carry" of holding one currency versus another.

The practical implication: when interest rate differentials are large, hedging is expensive.

In 2023-2024, when US interest rates were 5%+ and UK rates were approximately 4-5%, hedging USD/GBP cost approximately 0-1% per year. When UK rates were near zero (2020-2021) and US rates were rising, hedging USD/GBP cost approximately 4-5% per year — a substantial drag on returns for any UK investor holding USD assets with a hedge.

This creates a framework for cost-benefit analysis: is the certainty value of hedging worth more than the carry cost?

Hedged vs Unhedged ETFs: The Long-Term Evidence

Most major index ETFs come in both hedged and unhedged versions. A GBP-hedged S&P 500 ETF removes the USD/GBP exchange rate effect. An unhedged version carries the currency return — which can be positive or negative.

The long-run empirical evidence on whether hedging adds or subtracts value for equity investors is reasonably clear: over long periods (10+ years), currency effects in equity portfolios tend to wash out. A study of US equity returns for GBP-based investors over different 10-year periods shows that sometimes the unhedged version outperformed (when USD strengthened) and sometimes the hedged version outperformed (when USD weakened). Over the very long run, neither consistently dominated.

The cost of hedging (carry costs, transaction costs) means that the hedged version typically lags the unhedged version by approximately the carry cost over time, unless the currency moves consistently in the "wrong" direction for the unhedged investor.

The conclusion for long-term equity investors: for equity portfolios with a horizon of 10+ years, currency hedging is often not worth the cost. The currency effect washes out and the carry cost is a predictable drag on returns.

The conclusion for bond investors: different. Bond returns are typically 3-6% per year for investment-grade bonds. A 3-5% carry cost of hedging could consume the majority of the bond return. However, currency volatility in bond portfolios is much larger relative to the base return than in equity portfolios — meaning unhedged bond portfolios can have returns dominated by currency, not the underlying bonds. For this reason, many fixed income investment frameworks recommend hedging the currency in bond allocations, even at a meaningful cost.

Natural Hedging: Matching Assets and Liabilities

The most elegant currency hedging strategy is often not a derivative instrument at all — it is structuring the portfolio so that assets and liabilities are in the same currency naturally.

Examples of natural hedges:

• A British expat living in Cyprus who earns EUR, spends EUR, and holds EUR-denominated investments has no EUR/GBP currency risk
• A family with UK school fees (GBP) and a UK mortgage (GBP) who earns GBP has no currency mismatch on those obligations
• An investor expecting to retire in Portugal (EUR spending) who holds EUR-denominated bonds and European equities has partial natural hedging on the retirement spending obligation

The concept of "home bias" in investment portfolios — a tendency to overweight domestic equities — is often explained behaviourally as investor familiarity. It can also be understood as a partial natural hedge: a UK investor who works in the UK, owns a UK home, and will spend in GBP in retirement has a natural GBP liability; holding GBP assets reduces currency mismatch.

For internationally mobile investors, the "home" currency may shift over time. A professional who spends 10 years in Dubai, then 10 years in Singapore, and plans to retire in Portugal has a shifting set of natural obligations. The portfolio should evolve alongside the changing functional currency.

A Practical Framework for Currency Hedging Decisions

Rather than hedging all currency exposure or none, a structured framework:

Step 1: Identify your functional currency for each time horizon. Short-term (1-3 years): the currency you are currently spending in. Medium-term (3-10 years): the currency of any large planned obligations (property purchase, education fees, business transaction). Long-term (10+ years): the currency of your expected retirement spending.

Step 2: For short-term, known obligations — hedge explicitly. A property completion, a school fees payment, a large business payment in a foreign currency — these are known obligations where a forward contract provides certainty at a manageable cost. The carry cost of hedging a specific 6-12 month obligation is modest and the certainty value is high.

Step 3: For long-term equity allocations — generally do not hedge. The carry cost is a certain drag on returns; the long-run currency effect is uncertain and tends to wash out. Unhedged global equities are the standard approach for long-horizon investors.

Step 4: For bond allocations — consider hedging to functional currency. Bond returns are smaller and currency volatility is proportionately larger. Holding bonds in your functional currency, or hedging foreign currency bonds back to your functional currency, is generally a more defensible approach.

Step 5: For the retirement currency mismatch — address through gradual rebalancing. If your retirement spending currency is EUR and your portfolio is predominantly GBP, the transition from GBP to EUR should be gradual and systematic — converting a fixed GBP amount monthly over several years. This achieves a natural average rate without the cost of long-dated forward contracts.

How Global Investments Can Help

Currency strategy is an integral part of portfolio construction for internationally mobile investors. Global Investments helps clients identify their true currency exposures, decide which require explicit management, and implement appropriate instruments — from systematic conversion programmes through to forward contracts for specific obligations.

Our advisers work with specialist currency brokers to ensure clients access institutional-grade rates on larger conversions, and we integrate currency strategy into the broader financial plan — including the tax implications of currency gains and losses.

Currency markets can be highly volatile. Forward contracts and other hedging instruments involve costs and risks. The value of investments can fall as well as rise. Past exchange rate movements are not indicative of future movements. This article is for general information only and does not constitute financial advice.