A worked example: a DEGIRO investor with €50,000 in a world ETF, 2024–2026

The point of a worked example

Rules are easier to trust once you see them run against real numbers. This is a single, fictional case: an investor holding an accumulating world ETF at DEGIRO, followed from the 2024 purchase through the 31 December 2025 step-up to a partial sale in 2026. Every figure below is an illustration to show how the pieces fit, not a claim about any specific fund's returns or a prediction of yours. Your own numbers, and the current rates, are what matter — check them before relying on anything here.

The setup

• Investor: files a Belgian annual return, holds one position.
• Broker: DEGIRO — established abroad, so TOB and any tax on gains fall to the investor.
• Position: €50,000 invested in an accumulating world ETF in mid-2024. Being accumulating, it pays no dividend, so there is no yearly withholding to track.

Line 1 — TOB on the purchase

The ETF is an accumulating fund registered in Belgium, so the 1.32% TOB rate applies to the purchase. On €50,000:

• 1.32% × €50,000 = €660.
• The per-transaction cap for this rate is €4,000, far above €660, so the full 1.32% is due.

Because DEGIRO does not withhold TOB, this €660 is filed through the monthly TOB declaration for the month of the trade. Nothing about the position is taxed again until something is sold — an accumulating fund produces no dividend line in between.

Line 2 — The 31 December 2025 step-up

Say the position has grown to €57,000 by 31 December 2025. Under the step-up, that value becomes the new cost basis for the capital-gains tax that starts in 2026. The €7,000 of growth up to that date sits below the step-up line and is outside the new tax.

This is the single most important number in the example: gains are measured from €57,000, not from the original €50,000.

Line 3 — A partial sale in 2026

Suppose that in late 2026 the investor sells half the position for €32,000, when the whole holding is worth €64,000.

• Half of the step-up basis is €57,000 ÷ 2 = €28,500.
• Taxable gain = €32,000 − €28,500 = €3,500.
• The annual exemption is applied first; only the part of the gain above it meets the 10% rate.
• The sale also carries TOB: 1.32% × €32,000 = €422.40, again filed by the investor.

Measured from the original purchase price, the "gain" would have looked like €32,000 − €25,000 = €7,000 — twice as large. The step-up is exactly why the taxable figure is €3,500, not €7,000.

What the investor actually files

Pulling the three lines together, this DEGIRO investor reports, across the monthly TOB return and the annual return:

• TOB: €660 on the purchase, €422.40 on the partial sale.
• Capital gains: a €3,500 gain measured from the step-up value, reduced by the annual exemption before 10% applies.
• Dividends: none — the fund accumulates.

None of it was withheld by the broker, so all of it is the investor's to declare.

From export to these lines

The figures above are what Belfolio reconstructs from a DEGIRO export: it reads the purchase and sale, applies the correct TOB rate and cap, carries the 31 December 2025 step-up value, and measures the gain from it rather than from the original cost. It reports these numbers so you can see and check them — the decision to file, and the responsibility for the figures, remain yours. Treat this example as an illustration of the method and confirm every rate and value against your own documents.

The same can be replayed without an export: the stock exchange tax simulator and the capital gains tax simulator each price one order and one sale on their own.