Because we’re about to tax unrealized gains in Box 3…
Let that sink in for a moment.
You may soon pay tax on investment profits that only exist on paper.
Your ETF portfolio goes up €20,000 this year?
You could owe thousands in tax… even if you didn’t sell a single share.
No cash. No realized profit. Just market movement.
For years, investors complained about the fictional “forfaitaire rendement.” The system taxed returns people never actually earned.
Now we’re moving to the opposite extreme.
Instead of taxing fictional income, we may start taxing fictional liquidity.
Markets go up → tax bill arrives.
Markets crash next year → the money is gone, but the tax was already paid.
This fundamentally changes how long-term investing works in the Netherlands.
Long-term investors are normally rewarded for patience.
Compounding works because gains remain invested.
But taxing unrealized gains introduces a new dynamic:
investors may be forced to sell assets to pay taxes.
That’s not investing anymore. That’s liquidity management.
The goal of a fairer system makes sense.
But fairness should also consider cash flow, volatility, and the reality of how markets behave.
We’re entering a period where Dutch investors, entrepreneurs, and professionals will seriously rethink where and how they build wealth.
