Wise

I noticed Wise is paying me 3.85% on my USD.

I use my wise account to transfer money from my company share account in USD, so it's already in USD.

I was wondering what the disadvantage of leaving it in the wise account was in USD given it's gaining interest.

I guess I am unknowingly doing currency speculation and depending on the USD value.

If your main currency for purchases in EUR, then you should keep your savings in EUR.

You could loose a lot more than the interest gain via FX fluctuations.

But if you do decide to keep USD savings, you can do better than Wise - Lightyear will pay you 4.50% and Trading212 will pay you 5.10%.