Currency Overlay: Managing FX Risk Separately

Key Takeaways

• A currency overlay is a separate program of forward contracts that manages the FX exposure embedded in a foreign portfolio without buying or selling any of the underlying assets.
• The hedge ratio, the share of foreign-currency exposure that is hedged, is the central lever; common choices are 0% (unhedged), 50%, and 100%.
• A passive overlay simply targets a fixed hedge ratio to reduce currency volatility; an active overlay varies the ratio to try to add return from currency views.
• Performance is judged against a currency benchmark, typically the return of a stated fixed hedge ratio, so skill is measured as deviation from that reference.

What It Is

A currency overlay is a distinct mandate, often run by a specialist, that sits on top of an existing international portfolio and manages only its foreign-exchange risk. The equity or bond manager keeps picking assets; the overlay manager trades currency forwards to hedge, or partially hedge, the exchange-rate exposure those assets create.

Two ideas define it. The hedge ratio is the fraction of foreign-currency value covered by hedging contracts. A currency benchmark sets the neutral position: it states what hedge ratio the overlay is expected to hold, so the manager is measured against that stance rather than against zero.

Overlays come in two flavors. A passive overlay mechanically holds the benchmark hedge ratio to dampen currency swings. An active overlay treats currencies as a source of return, raising or lowering the hedge ratio based on a view.

The Intuition

Currency and asset returns do not have to move together, so bundling them wastes information. A US investor might pick excellent European stocks yet still lose money if the euro falls against the dollar. Managing the two separately means the stock decision and the currency decision each get made on their own merits.

Separation also matches expertise to the job. Trading FX forwards well is a different skill from selecting equities, and forwards are cheap and liquid, so hedging rarely requires disturbing the real holdings. The overlay is the accounting device that keeps those decisions, and their profit and loss, cleanly apart.

How It Works

The overlay manager measures the portfolio's exposure to each foreign currency, then sells that currency forward (or buys it) to reach the target hedge ratio. A forward locks in an exchange rate for a future date, so a gain on the forward offsets a loss on the currency value of the assets, and vice versa.

The forward rate is not the spot rate. It is set by the interest-rate difference between the two currencies through covered interest parity, so hedging a high-yield currency into a low-yield one usually earns a small positive carry, and hedging the other way costs carry. Contracts are typically one to three months and rolled at expiry.

Because prices move, exposures drift from the target, so the forwards are resized on a schedule. An active overlay deliberately lets the hedge ratio move away from the benchmark when the manager has a view; a passive one rebalances straight back.

Worked Example

A US investor holds a euro-denominated equity portfolio worth EUR 10,000,000. At the start of the quarter EUR/USD is 1.10, so the position is worth USD 11,000,000.

Over the quarter the equities rise 5% in euro terms to EUR 10,500,000, but the euro weakens to EUR/USD 1.05.

• Unhedged: the USD value becomes 10,500,000 x 1.05 = USD 11,025,000, a return of just 11,025,000 / 11,000,000 - 1 = 0.23%. The 5% stock gain was almost entirely erased by the currency.
• 50% overlay: the manager sold EUR 5,000,000 forward at 1.10 (a 50% hedge ratio). At settlement, selling euros at 1.10 when spot is 1.05 gains (1.10 - 1.05) x 5,000,000 = USD 250,000. Total value is 11,025,000 + 250,000 = USD 11,275,000, a return of 275,000 / 11,000,000 = 2.50%.

The overlay changed the currency outcome by USD 250,000 without the equity manager trading a single share. Note that a 100% hedge set on the starting EUR 10,000,000 would still leave the EUR 500,000 gain unhedged, which is why hedge ratios drift and must be rebalanced.

Common Mistakes

1. Confusing a hedge ratio with a return forecast. Choosing 100% hedged is a volatility decision, not a bet that the currency will fall. Setting the benchmark ratio first, then judging active tilts against it, keeps the two separate.
2. Ignoring the cost of carry. Hedging a high-interest currency into a low-interest one earns carry, but hedging the reverse pays it away every roll. Over years that drag can outweigh the volatility saved.
3. Forgetting to rebalance. As assets and exchange rates move, a fixed forward notional no longer matches the exposure, so an unrebalanced hedge slowly becomes the wrong size.
4. Hedging currencies you are paid to hold. For assets like emerging-market bonds, the currency is part of the expected return, and hedging it away can defeat the reason for owning them.

Frequently Asked Questions

Q: What is a currency overlay in plain terms? A currency overlay is a separate program that manages the foreign-exchange risk of an international portfolio using forward contracts, without buying or selling any of the underlying stocks or bonds. It lets a specialist handle currency while the asset manager handles assets.

Q: How does a currency overlay differ from just hedging inside the fund? Both use the same forward contracts, but a currency overlay is a distinct mandate with its own benchmark and profit and loss, so the currency decisions and their results are measured on their own rather than blended into the asset manager's numbers.

Q: What hedge ratio should an overlay use? There is no single answer. Many long-term equity investors sit near 50% because it splits the difference between currency risk and hedging cost, while bond investors often hedge closer to 100% since currency swings can dwarf a bond's own return.

Q: Does a currency overlay guarantee lower risk? No. A passive overlay reduces currency volatility, but an active overlay that takes currency views can add risk, and even a hedge carries basis and rebalancing risk. Hedging also removes upside when the foreign currency rises.

Q: What benchmark is used to judge a currency overlay? The benchmark is usually the return of a stated fixed hedge ratio, such as fully hedged or 50% hedged. The overlay manager's skill is then measured as the value added above or below that neutral hedging stance.

Sources

1. Investopedia. "Currency Overlay." https://www.investopedia.com/terms/c/currency-overlay.asp
2. Investopedia. "Hedge Ratio." https://www.investopedia.com/terms/h/hedgeratio.asp
3. Investopedia. "Forward Contract." https://www.investopedia.com/terms/f/forwardcontract.asp
4. Investopedia. "Currency Risk." https://www.investopedia.com/terms/c/currencyrisk.asp

Disclaimer

This article is educational content only and is not financial advice. Nothing here is a recommendation to buy, sell, or hold any security. Consult a licensed advisor before making investment decisions.