Money in more than one currency
If everything you own is in one currency, skim this lesson and move on. If you have worked abroad, hold foreign shares, send money home, or plan to retire in a different country from the one you earn in, this is the lesson that prevents years of confusion.
Pick one base currency
Section titled “Pick one base currency”The first decision, and it only needs making once.
Your base currency is the one your total net worth is expressed in. Every holding gets converted into it so that one number means something.
Choose the currency you will spend in the long run — usually where you expect to live and retire, not necessarily where you earn today. If you are genuinely undecided, use the currency of your largest liability, since that is the obligation you must eventually meet.
What matters most is that you pick one and keep it. Switching base currency every year makes your history uncomparable.
Two different rates, two different jobs
Section titled “Two different rates, two different jobs”This is the distinction that causes most errors.
Current rate — for value. What is this holding worth today, in my base currency? Always use today’s exchange rate.
Historical rate — for cost. What did this holding cost me, in my base currency, on the day I bought it? Use the rate from the purchase date, and never update it.
Getting these the wrong way round produces returns that are simply wrong. A tool that converts your purchase price at today’s rate will silently rewrite your history every time the currency moves.
Currency gain is not investment gain
Section titled “Currency gain is not investment gain”Here is the case worth internalising.
You are based in Europe and buy 10,000 USD of a US index fund when the rate is 1.00 EUR/USD. Cost: 10,000 EUR.
A year later the fund has risen 8%, to 10,800 USD. But the dollar has weakened to 1.20 EUR/USD. Your holding is now worth 9,000 EUR.
The fund made 8%. You lost 10% in euros.
Neither figure is wrong. They answer different questions:
- Local return measures the investment decision. Was this fund a good pick?
- Base-currency return measures your actual wealth. Can I buy more than I could before?
A good tracker shows you both. If yours only shows one, you cannot tell skill from exchange-rate luck.
What this means in practice
Section titled “What this means in practice”Do not panic at currency moves. If your home currency strengthens, foreign assets shrink on paper without anything happening to the underlying investments. This reverses. It is noise unless you are about to convert.
Match currency to future spending where you can. If you will retire in a particular country, holding a meaningful share of your assets in that currency removes risk you are otherwise carrying for no return.
Watch conversion costs. Banks routinely charge 2–4% on retail conversions, usually hidden in the rate rather than shown as a fee. Moving money repeatedly between currencies is expensive in a way that does not appear on any statement.
Remember debts have currencies too. A loan in a currency you do not earn in grows in real terms when that currency strengthens. This has ruined people who borrowed in a “cheap” foreign currency.
Do the conversion in one place
Section titled “Do the conversion in one place”A practical warning. If your tracker converts currencies in one place, your spreadsheet in another, and you do some mental arithmetic on top, the numbers will disagree and you will not know which to believe.
Have one system that owns the conversion, using one rate source, applied consistently. Whether it is right in the last decimal matters far less than it being consistent.
Practice step
Section titled “Practice step”Work out what share of your net worth sits outside your base currency.
Add up everything held in other currencies, convert at today’s rate, and divide by your total.
If it is above 30%, currency movement is a real driver of your net worth, and worth watching alongside your investments. Most people with international lives are surprised by how high this figure is.
Module 3 complete. Your portfolio exists in one place, entered sensibly, in one base currency.
Next: Module 4 — Ask questions about your own data, where the AI finally stops guessing.
Agni Folio converts every holding into your chosen base currency with daily rates, using purchase-date rates for cost basis and current rates for value — the distinction this lesson is about.