Box 3 Is Changing in 2028 — What It Does to Your FI Plan

Your FI number assumes the Box 3 wealth tax works today's way forever. It won't. The Dutch government is legislating a shift from deemed-return (taxing imagined returns on your wealth) to actual-return (taxing real gains your portfolio produces). Targeted for 2028 but not yet final, this reform changes what "tax-efficient" means for a large invested stash. Understanding what's coming — and what to do while today's rules still apply — matters if you're building toward financial independence in the Netherlands.

The current system (deemed return): tax wealth, not income

Today, Box 3 taxes imagined returns, not actual ones. The Belastingdienst sets a fixed rate on January 1st — 6% on investments, 1.28% on cash — and taxes that at 36%, regardless of real performance. Whether your shares rose 20% or fell 10%, the tax is the same. This is the system every FI calculator assumes will continue.

Since the Dutch Supreme Court's 2021 ruling that this system violated property rights when real returns fell below deemed ones, the government has been legislating change. For the current system's full mechanics, see the Box 3 guide.

What the reform changes: actual gains become taxable

The Wet werkelijk rendement box 3 (Actual Return Box 3 Act) targets 2028, but the bill is still in parliament and the final version may differ. Treat timeline and mechanics as directional, not finalized.

The shift: tax actual realized and unrealised capital gains plus a smaller deemed return on cash (roughly 0.5–1% instead of 1.28%). This means:

• Unrealised gains become taxable yearly. An ETF worth €50,000 with €10,000 unrealised gain is now taxable income that year, whether you sell it or not. Today's system ignores unrealised gains.
• Worldwide assets stay in scope. You can't escape Box 3 by holding US stocks or crypto abroad.
• The tegenbewijsregeling (counter-evidence scheme) continues. If actual returns fall below the legal threshold, you can claim the lower amount.

For FI: someone drawing on investments now faces tax on unrealised gains, shrinking the stash annually even without selling. A €1.5 million portfolio with 5% yearly unrealised gain generates €75,000 new taxable gains yearly — this is part of the Box 3 drag on your FI stash you need to account for.

The 2026–2027 window: clean valuations before the switch

The transition creates a window to establish baseline valuations for the switchover. When the actual-return system launches, authorities need to know: what was your portfolio worth on day one? Getting documented valuations now (broker statements, cost-basis records, professional appraisals if needed) prevents disputes over your starting point later.

This isn't a reason to panic-trade. It's a reason to ensure accurate broker statements and, if you hold illiquid assets abroad (real estate, private equity, crypto), to get a professional valuation on file.

What to do now: stay the course, document everything

Keep your current FI plan. Deemed-return is law today; the FIRE-number calculator uses it, and you should build around today's rules. The calculators model 2026 rates with a footer note that Box 3 reform is pending — they don't include speculative "what if" scenarios because the bill isn't final. This guide is where the topic lives.

Document valuations. Keep broker statements, cost-basis records, and any professional valuations. When the law passes, the Belastingdienst will specify what it accepts for switchover valuations. Good record-keeping is your future-proofing.

Revisit when the bill is final. Once law — likely late 2027 for 2028 start, though timing is uncertain — recalculate your FI number using actual expected returns and estimated annual gains. Your real number may shift based on asset allocation and market expectations, but that's a conversation to have once you know the actual rule.

Watch Tweede Kamer/Eerste Kamer status and Belastingdienst Box 3 pages for updates. A tax advisor can model your specific situation once the reform is final.

Watch the legislative calendar, revisit your plan when it's law

The Dutch wealth-tax system has been in transition since 2022. This reform is the next step, but not yet law — the Senate position and amendments could shift timeline and details. Don't treat 2028 as definite or assume current mechanics will match. Instead, watch the bill progress, keep financial records clean, and when parliament passes the reform, revisit your FI plan with the actual rules in hand.