Saving
Holding money in another currency adds a second thing that can move
A balance abroad has two variables rather than one, because what it earns and what it is worth in your own currency are determined by entirely separate forces.
By Aditya Ramaswamy3 min read
Two numbers, only one of which is advertised
A savings balance in your own currency has one moving part: the rate it earns. A balance held in a foreign currency has two. It earns whatever that currency’s savings rates offer, and it is worth whatever the exchange rate says on the day it is converted back. Those two are set by different mechanisms and there is no reason for them to move helpfully together.
This matters because the second variable is usually much larger than the first. Exchange rates can move by several per cent in a matter of weeks, which dwarfs the difference between a good savings rate and a poor one over the same period. A household comparing rates across currencies and ignoring the exchange component is comparing the smaller number.
An illustration with invented figures. A balance abroad earns 6% over a year while the home currency strengthens 8% against it. Measured at home, the year produced a loss, despite the account performing exactly as advertised.
Why the higher rate is not free money
It is a persistent intuition that money should be moved to wherever savings rates are highest. The difficulty is that rate differences between currencies are not an oversight. They reflect, among other things, differences in expected inflation and in the risks attaching to that currency, and markets price the forward exchange rate accordingly.
That does not mean the trade never pays. It means the higher rate is compensation for something rather than a discovery, and the something is generally the possibility that the currency loses value. Whether it does is genuinely uncertain, which is precisely the point.
The theory here is contested in its details and imperfect in practice, and people do make money on such positions. But treating a rate difference as a straightforward gain, with the exchange rate as an afterthought, misreads what is being bought.
Conversion is a transaction with a spread
Moving between currencies is not free, and the cost is often invisible because it is embedded in the rate offered rather than charged separately. The gap between the rate at which a provider buys a currency and the rate at which it sells is the spread, and it is a real cost paid on the way in and again on the way out.
Advertised fee-free conversion frequently means the charge is in the spread instead. The way to see the true cost is to compare the rate offered with the mid-market rate at the same moment, which is published and easy to check. The difference, plus any explicit fee, is what the transaction actually costs.
For a household converting occasionally, this is a modest one-off. For one moving money regularly — supporting family abroad, receiving payment in a foreign currency, splitting life between two countries — it accumulates into something worth shopping around for.
When a foreign balance is the low-risk option
The framing changes completely when the money has a job in that currency. Someone paying for a child’s education abroad, holding property overseas, or planning to retire in another country has liabilities in that currency, and holding the matching currency reduces their exposure rather than increasing it.
This is the useful principle: currency risk is about the mismatch between what you hold and what you will need to spend. A balance in your own currency is not inherently safe, it is merely matched. Once a substantial future cost is denominated elsewhere, the matched position may be the foreign one.
The same logic explains why holding a modest amount of a currency you travel to regularly can be sensible convenience rather than speculation. The scale is small and the purpose is real.
The practical constraints people meet
Beyond the arithmetic there are administrative realities that vary enormously by country: what a resident is permitted to hold abroad, what has to be declared, how income earned overseas is treated, and whether deposit protection applies to an account held outside your own jurisdiction. These are not minor details and getting them wrong is expensive in ways unrelated to exchange rates.
Access can be slower too. Money in a foreign account may take longer to reach you and may arrive after a conversion at a rate you did not choose, which makes it a poor location for a buffer that exists to be reached quickly.
All of which is why this is territory where general explanation runs out early. Rules differ by country and change, tax treatment is specific to individual circumstances, and anyone holding a meaningful sum across borders is better served by regulated advice covering their own situation than by any principle stated here.
Common questions
Should I move savings to a currency with higher interest rates?
The higher rate generally reflects higher expected inflation or greater risk attaching to that currency rather than a free advantage, and the exchange rate can move by far more than the rate difference. It can work out and it can fail badly. For anything substantial this belongs with a regulated adviser rather than a rule of thumb.
How do I find the real cost of converting money?
Compare the rate you are offered against the mid-market rate at that moment and add any explicit fee. The difference is the total cost, and it is often larger than a headline claim of no commission suggests. Providers vary considerably on this.
Is it sensible to hold some money in a currency I travel to?
For amounts proportionate to actual spending there, it is a matter of convenience and removes the need to convert under time pressure. It becomes something else once the balance is large relative to the purpose, at which point the exchange rate is doing more work than the convenience is.
Aditya covers spending, saving, debt and the questions readers actually send in and thinks most subjects are more interesting once you know how they work.
