What it means
An investor buying foreign shares receives two kinds of exposure: the shares can gain or lose in their local market, and the foreign currency can rise or fall against the investor's reporting currency. Separating those effects helps a portfolio team decide which risk to keep.
An overlay manager need not sell the foreign securities to change currency exposure, because it can enter a currency hedge against a portion of their value while the stocks remain in the portfolio. The CFA Institute's currency-management reading discusses the range from fully hedged exposure to active currency management.
The choice belongs in an investment policy, not in a last-minute reaction to a headline, and a full hedge can reduce some exchange-rate swings but may also remove favourable currency gains. The choice of reporting currency matters too, since a global investor measuring returns in dollars may want a different hedge from a pension paying benefits in euros, so align the overlay with liabilities and investor objectives rather than a universal rule.
A passive overlay tries to maintain a preselected hedge ratio, so if the foreign portfolio grows or shrinks the notional of the currency hedge may need adjustment, and ignoring changes can leave the hedge too large or too small. An active overlay allows positions based on a currency view, where its manager may intentionally hold more or less exposure than the neutral target.
That is an investment decision with potential upside and downside, not a pure risk-removal service. Foreign-exchange forwards can lock a rate for a future exchange, but they have settlement and counterparty terms.
Options provide different payoffs and often require premiums, so each tool's costs and liquidity demands should be compared with the portfolio mandate. A hedge ratio of 50% is a target, not a promise to remove half of every daily fluctuation, because asset prices, currency values and timing all move and basis differences and transaction costs can leave residual currency exposure.
Cash management matters because derivative positions can require collateral or settlement payments. A portfolio may show a favourable economic hedge but need liquid cash before its foreign assets can be sold, so set liquidity reserves and controls in advance.
A manager should document permitted instruments, hedge ranges, counterparties and decision rights, and if an external overlay manager acts separately from the asset managers, holdings data must arrive accurately and promptly, since a stale portfolio value can produce a mis-sized hedge. For a non-finance reader, think of two knobs: asset selection and currency exposure.
An overlay turns the second knob without necessarily touching the first, and the goal and allowed range should be stated before judging whether it worked.
In practice
Real-world examples.
Example
A dollar-based fund owns euro-denominated bonds. It keeps the bonds but sells euros forward to reduce the effect of a euro decline on its dollar value, and it reports the bond return and the hedge result separately.
Example
A pension sets a 50% target hedge for its foreign equities. As the equities rise, it adjusts the forward notional to stay near that target, using a monthly valuation supplied by its custodian.
Example
An active manager expects one currency to strengthen and leaves more exposure to it. The decision adds risk and is measured separately from the local stock return, with limits agreed in advance by the investment committee.
Formula
Calculation
Target hedge notional = foreign-currency asset exposure x chosen hedge ratio. If a portfolio holds EUR 2 million of euro assets and targets a 50% hedge, the illustrative hedge is EUR 2 million x 50% = EUR 1 million. Revalue exposure and include instrument costs, cash needs and any mismatch before calling the target achieved.
Rebalancing follows the same arithmetic. If the euro assets rise 10% to EUR 2.2 million, the 50% target becomes EUR 2.2 million x 50% = EUR 1.1 million, so the manager increases the hedge by EUR 1.1 million - EUR 1 million = EUR 0.1 million. Without that adjustment the effective hedge ratio would drift down to EUR 1 million / EUR 2.2 million, or about 45%.Case study
Seen in the real world.
Fictional case: A university endowment owns international stocks and reports results in dollars. Its committee decides to hedge half of the developed-market currency exposure while leaving emerging-market exposure unhedged. An overlay manager receives updated holdings monthly, uses approved forward counterparties and tracks collateral. A euro rally makes the hedge look costly relative to unhedged performance, but it had been chosen to reduce volatility rather than predict the euro.
The committee reviews asset returns and currency overlay results separately before changing policy. The following year the committee notices that stale holdings data left the hedge slightly oversized after a strong equity quarter. It asks the custodian for faster valuations and adds a tolerance band around the 50% target. The illustrative lesson is that an overlay is a process with data, limits and reporting, not just a derivative trade.
Watch out
Common mistakes.
- Assuming hedging currency risk also removes the underlying asset's market or credit risk.
- Calling an active currency bet a passive hedge without stating the target exposure.
- Ignoring derivative settlement, collateral and manager fees when assessing the overlay.
Questions
People also ask.
Must the foreign investments be sold?
No. An overlay can change currency exposure through separate instruments while leaving the assets in place.
Will a full hedge guarantee a fixed portfolio value?
No. The underlying assets still move, and hedge costs and mismatches remain.
What should performance be compared with?
Use the pre-agreed currency target and report local asset return and overlay contribution separately.
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