Trading in non-EUR: should I convert first?

FX on non-EUR trades (should I convert before trading?)
When you buy or sell a stock or ETF that’s priced in a currency other than euro (e.g., USD or GBP), there’s an FX conversion between EUR and that market’s currency. This conversion has a rate and usually a small fee/spread. You’ll also take on currency risk: if the foreign currency falls against EUR, your investment’s EUR value can drop even if the share price stays the same.

Converting before you trade can give you cost certainty. You switch a lump sum from EUR to (say) USD, see the FX rate up front, and then place your USD trades without extra conversions each time. This helps if you plan several buys/sells in the same currency, or if you’ll receive dividends in that currency. The trade-off is you’ll be holding foreign cash, so its EUR value will move with exchange rates.

Letting the platform convert per trade might be simpler. You place the order in EUR and the system converts only the amount needed at execution. This avoids holding foreign cash, but you may pay a conversion each time you buy or sell, and if you deal in multiple currencies you could face multiple conversions over time. Dividends or sale proceeds in a foreign currency may also be converted back to EUR if you don’t hold that currency.

There isn’t a single “best” choice. If you expect many transactions in the same currency, pre-converting can reduce repeated FX conversions and makes costs predictable. If you expect occasional trades, per-trade conversion keeps things simple but do keep in mind that exchange rates affect your return in euro: a stock can rise in USD while your EUR value falls if the dollar weakens.