What the Reynders tax is
The Reynders tax — officially article 19bis CIR92 — taxes at 30% the interest component of the gain you realise on the sale, redemption or liquidation of units in a fund that invests more than 10% in debt claims. That component is the taxable income per share or TIS: the part of your gain that counts fiscally as interest rather than as a capital gain. Bond ETFs and mixed funds are the typical candidates; a fund with no meaningful debt holdings does not reach the threshold.
Why everyone wrote that it would disappear
In April 2025, a widely cited commentary on a draft of the capital gains tax appeared, under which the Reynders tax would disappear once the new tax entered into force. The firm behind that commentary withdrew the reading itself in July 2025 — but by then "the Reynders tax is going away" had settled in everywhere, and many of those articles are still online today.
The enacted law of 6 April 2026 (Belgian Official Gazette of 21 April 2026, with effect from 1 January 2026) says otherwise. It mentions article 19bis nowhere, and the CIR92 modification index on Justel lists no 2025 or 2026 law touching it. What the law does do: its article 10 inserts article 96/2, first paragraph, 6° CIR92, exempting from the capital gains tax the income already taxable as movable income. That is coordination between the two taxes — not abolition of the older one.
How the two taxes combine
Circular 2026/C/74 of 22 July 2026 (margin numbers 201–204, available on Fisconetplus) fixes the order:
- Compute the Reynders tax first: the interest component (TIS) at 30%.
- Deduct that base from the realised gain.
- The remainder falls under the 10% capital gains tax — and only against that residual slice does the annual €10,000 exemption count.
If the fund publishes no TIS, the calculation falls back to a split along the asset test (the fund's share of debt claims); if that figure is missing too, the entire gain is taxed at 30% — and nothing is left for the 10%.
A worked example
You sell a mixed fund in 2026. The realised gain is €15,000 (measured from the 31 December 2025 step-up value for units acquired before 2026), of which €4,000 is interest component according to the fund's TIS figures. You realise nothing else that year.
- Reynders tax: €4,000 × 30% = €1,200.
- Residual slice: €15,000 − €4,000 = €11,000.
- Exemption, here only: €11,000 − €10,000 = €1,000.
- Capital gains tax: €1,000 × 10% = €100.
Together €1,300, and not one euro taxed twice. Ignoring the Reynders tax gives (€15,000 − €10,000) × 10% = €500 — a figure that both overstates the 10% leg (€500 instead of €100) and misses the €1,200 charge entirely.
What this means if you hold such a fund
One sale can therefore carry two taxes, each on its own slice. The reference that decides whether your fund is in scope is the asset test: more than 10% debt claims. For units acquired before 1 January 2018 the threshold was 25% — whether that older threshold carries through the 2026 regime unchanged, and whether it is tested per purchase lot so that one fund can be in scope for one lot and out for another, are points we have not yet seen confirmed.
For the 10% leg, nothing changes from what is described elsewhere: anyone who opted out or invests through a foreign broker calculates and declares on their own.
What Belfolio computes today — and does not yet
Belfolio does not yet compute the 19bis leg: that would require TIS figures per fund, and no open dataset of them exists. As long as that holds, the calculator does not present a capital gains figure on the sale of such a fund as settled: it shows it with the reason — the 10% base is then overstated and a 30% charge is missing.
Which funds fall in scope, we curate fund by fund, with source and date. The per-fund pages show the status per ISIN — including "unknown" when that is the honest answer.
To be confirmed. Whether the 25% threshold for pre-2018 units carries through the 2026 regime unchanged and is tested per lot, and what status each individual fund has: none of this is confirmed at the time of writing. The per-ISIN curation is ongoing; treat any figure resting on these points as uncertain.
Verify your figures
Belfolio shows this calculation for information only. This is not tax advice. Check your situation with the FPS Finance or your accountant before filing.
Published 3 Sept 2026
Frequently asked questions
- Is the Reynders tax abolished now that the capital gains tax exists?
- No. The law of 6 April 2026 does not mention article 19bis CIR92 anywhere; the tax continues to apply unchanged. On the sale of a fund in its scope, the interest component is taxed at 30% first, and the 10% capital gains tax falls on the remainder.
- Do I then pay tax twice on the same gain?
- No. Under Circular 2026/C/74, the Reynders tax base is deducted from the gain before the 10% is calculated. Every euro of your gain falls into exactly one slice: either the 30% or the 10%.
- Does the €10,000 exemption also apply to the interest component?
- No. According to the circular, the annual exemption reaches only the slice subject to the 10%. The interest component bears the full 30%, however small your total gain.