Let me explain the rules regarding taxes and BLOX. Please keep in mind that we are not tax advisors, and for comprehensive advice, you can always visit the website of the Dutch or Flemish Tax Authority.
For the Netherlands
Cryptocurrencies fall under your assets in Box 3. This includes your possessions minus your debts, such as your savings account, stocks, or a second home.
Whether you have to pay taxes on your crypto depends on the total amount. In 2020, you paid taxes when the total amount was over 30,846 euros (61,692 euros with a tax partner), and in 2021, that amount increased to 50,000 euros (100,000 euros with a tax partner).
In March 2022, you must declare what you owned in coins on January 1, 2021.
For example, if on January 1, 2021, your savings account had 10,000 euros, and your cryptos were worth 5,000 euros with no debts, you don't have to pay taxes. But if the total amount goes over 50,000 euros, you will have to pay taxes.
The rules for cryptocurrency and taxes are different. You don't have to pay taxes when you own cryptocurrency. The Federal Public Service of Finance (FPS) only comes into play when you convert your bitcoins to euros.
In that case, you may or may not have to pay taxes. The Advance Decision Service (ADS) states, "Investments in virtual currencies are usually speculative, and the income derived from them constitutes various incomes."
Please note the word "usually" in this sentence. It's unclear when you must pay taxes and when you don't. The FPS advises you to contact the ADS for personalized advice. You can find their contact information here.