Academy
Currency risk and conversion
- Currencies
- Risk
- Foreign assets
Anyone holding foreign stocks is really trading two things at once: the company itself and the currency the stock trades in. Even if the share price stays put, your portfolio's value can move — purely because of the exchange rate. This article explains where currency risk comes from, how it shows up over short and long horizons, and which tools dampen it.
Where movement comes from without a price move
Picture a European investor holding a US stock quoted in dollars. The share price doesn't change over a day, but the dollar weakens 2% against the euro. Converted back into euros, the investor is down 2% — even though nothing at all happened to the company.
With a foreign asset, both the share price and the exchange rate leave a mark on your result. The two add up.
This is currency (exchange-rate) risk: the uncertainty that comes from ultimately measuring a foreign-currency asset in your own home currency.
Quote currency vs. portfolio currency
It helps to separate two terms:
- Quote currency — the currency an asset trades in on its exchange (dollar, pound, yen…). The market sets it, not you.
- Portfolio currency — the currency you track and measure your wealth in (typically your home currency).
Between them sits a conversion at the current rate. An illustrative example: buy a stock at $100 with a rate of €0.90/$ and it costs you €90. If the stock rises to $110 but the dollar weakens to €0.82, you hold 110 × 0.82 = €90.20 — a 10% price gain shrank to almost nothing because the currency largely erased it. The reverse holds too: a weakening home currency can amplify a foreign gain.
Hedging
The currency effect can be limited by hedging. In practice, currency-hedged ETFs offer this: using currency contracts, they screen out the exchange-rate move so the return tracks the underlying asset rather than the currency.
Hedging isn't free, though:
| Aspect | What it means |
|---|---|
| Cost | Hedging costs money (interest-rate differentials, fees), which lowers return. |
| Symmetry | It screens out the loss from an adverse currency move — but also the gain from a favourable one. |
| Imperfection | Hedges are only approximate and are renewed periodically, so a small residual remains. |
Hedging is thus neither “better” nor “worse” — it just changes the nature of the risk. It makes more sense where the currency component isn't wanted (e.g. a short horizon) and less where currency variety is actually welcome.
Dividends and taxes in a foreign currency
Currency complicates income too. A dividend from a foreign stock arrives in a foreign currency, as does the tax withheld at source. For domestic bookkeeping and your tax return, both are converted to the home currency — usually at the rate on the relevant date — and the conversion of the tax and the gross amount has to line up. The mechanics of the taxation itself (withholding tax, credits, treaties) are covered in the separate article on how foreign dividends are taxed.
Short-term vs. long-term
The currency effect shifts with the horizon. In the short term, exchange rates can swing sharply and easily drown out the share-price move — for someone trading over a few months it's a decisive variable. In the long term, rates tend to move around longer-run levels and their impact on a well-spread portfolio softens, though it never fully disappears.
At the same time, currency need not be only a risk — it can also be part of diversification: holding assets in several currencies means not betting everything on the fate of a single one. It's one of the axes along which a portfolio can be spread — more in the article on diversification.
Where Invest Control helps
Invest Control records each asset's original currency and converts values at the current rate, so you see your portfolio uniformly in whatever currency you choose — across dollar, euro, pound and more. Because every asset is kept by its exchange and currency (a link explained in the article on ISIN, ticker and exchange), you can tell how much of your wealth actually hangs on which currency — so currency risk stops being invisible.