Tax gain harvesting with crypto: use your €10,000 exemption before 31 December

We have already written about tax loss harvesting: deliberately realising losses to lower your taxable capital gain. This article covers the opposite move: deliberately realising gains while they still fall within your exemption. Under the new capital gains tax, the first €10,000 of capital gains per calendar year is exempt. If you have not used up that room for 2026, December is the month to decide what to do with it. Below you can read how it works, where the pitfalls are and how to see your remaining room in Cryptotax.

Why December matters

The Law of 6 April 2026 (Belgian Official Gazette of 21 April 2026) introduces a 10% tax on capital gains on financial assets, including crypto, retroactively from 1 January 2026. Under normal management of your private assets, the first €10,000 of net capital gains per calendar year is exempt. The exemption belongs to a calendar year: whatever you want to count for 2026, you must realise in 2026, by 31 December at the latest. A sale counts in the year in which it takes place. So do not wait until the last day. You can read the full rules in our explanation of the €10,000 exemption.

What counts as "realising"?

Realising is not just cashing out to your bank account. Every sale of crypto for euro and every swap from one crypto to another (including to a stablecoin) is a realisation: at that moment a gain or a loss arises. A transfer between your own wallets and exchanges is not a realisation.

Losses from the same year are offset against your gains first. If you realised €5,000 in gains and €1,000 in losses in 2026, your net capital gain is €4,000 and you still have €6,000 of exempt room. Because losses do not carry over to later years, only what you realise yourself in 2026 counts.

What happens to your acquisition cost?

The capital gain is the difference between the sale price and the acquisition cost. For crypto you bought before 2026, the acquisition cost in principle starts from the value on 31 December 2025, as we explain in our article on the step-up rule. For purchases from 2026 onwards, it is your purchase price.

If you sell a position within the exemption and buy again later, you start that new position with a new, higher acquisition cost. A later gain on that position is then smaller. That is the mechanism behind "tax gain harvesting". But whether you may do this by buying straight back is an open question (see below).

Important for your calculation: the law imposes FIFO (art. 102, §1 ITC 92). When you sell, the oldest purchase of that coin is used first, across all your exchanges and wallets together, regardless of the platform you sell on. How this works in Cryptotax is explained in FIFO explained. The worked example below shows why it matters.

Worked example with round numbers

In 2026 you have already realised €3,000 of net capital gains. Your remaining exemption for 2026 is therefore €7,000. You also hold bitcoin, bought in two purchases:

• In March 2026 you bought 0.3 BTC on Bitvavo at €50,000 per BTC (€15,000 in total). That BTC is now on your hardware wallet.
• In June 2026 you bought 0.2 BTC on Kraken at €80,000 per BTC (€16,000 in total). That is still on Kraken.

Bitcoin is trading at €85,000 today. You sell 0.2 BTC on Kraken for €17,000.

Many investors would think: "I am selling the BTC I bought on Kraken at €80,000, so that is €1,000 of profit". But FIFO looks at your oldest bitcoin, across all your accounts together. The sale therefore uses the March purchase, at €50,000 per BTC. Your acquisition cost is 0.2 × €50,000 = €10,000, and your capital gain is €17,000 minus €10,000 = €7,000.

Together with the €3,000 from earlier you land exactly on €10,000: your full exemption for 2026 is used and you pay no capital gains tax for 2026. Had you sold 0.3 BTC, your capital gain would have been €10,500 and you would pay 10% on the €3,500 above the exemption, so €350. If you only sell the same 0.2 BTC in January 2027, that capital gain counts for 2027.

This example assumes normal management, no transaction costs and round numbers. Your own figures depend on all your transactions.

What about an unused exemption?

The law provides for a limited carry-over to later years (art. 96/2, first paragraph, 3° ITC 92). This is how we read the text: if you use less than €1,000 of your exemption in a year, the difference with €1,000 carries over to the next year. This can happen for at most five consecutive years, up to a total exemption of €15,000 in one year. If you have already used €1,000 or more of your exemption in a year, then according to that text nothing carries over.

In practice: if you realised no capital gains in 2026, you build up €1,000 of extra exemption for 2027. If you already realised €3,000 in 2026, as in the example, you build up no extra exemption. There is no circular yet that elaborates on this, so have your own situation confirmed by your accountant. Cryptotax does not yet include this carry-over in its calculation today.

And if I buy back afterwards?

If you buy again after a sale, you start with a new acquisition cost: the higher purchase price. A later gain on that position is then smaller. The Law of 6 April 2026 contains no explicit rule against selling and immediately buying back. That does not mean the risk is zero. The tax authority could argue that a sale and immediate repurchase is not a real transaction but a tax-motivated arrangement, especially if there is no other economic rationale behind it. Whether the tax authority would treat that as abuse remains open. Cryptotax therefore does not recommend buying back; discuss it with your accountant or tax adviser. You can read more about the same question for losses in our article on tax loss harvesting.

Mind normal management

The exemption and the 10% rate apply only to normal management of your private assets. If you trade very frequently or speculatively, you risk the tax authority treating the profit as speculative: then 33% applies and the exemption falls away. Many trades shortly before year-end to use up the exemption can reinforce that picture. Cryptotax calculates on the basis of normal management and does not judge your profile. You can read where the line lies in the prudent person test.

How Cryptotax shows your remaining room

1. Bring your transactions up to date

Your remaining exemption is only as complete as the data Cryptotax has. First synchronise your connected exchanges and wallets, and upload recent CSV exports from platforms without an API connection. Only then do all sales and swaps of 2026 count. A forgotten account can change your FIFO order and therefore your capital gain.

2. Check your remaining room for 2026

On your dashboard you see your realised capital gain for 2026 and how much of your €10,000 is still free. With a paid plan for 2026 you see the exact amount. Without a plan, Cryptotax shows a range, and you can unlock 2026 via the pricing page.

3. Plan a sale in the Sales Simulation

In the Sales Simulation you pick a position and see what a sale today would mean for your 2026 tax, and how much of it you can sell before you exceed your exemption. The simulation starts from the FIFO lots in your report. You can find more explanation on our page about using your exemption before 31 December.

In short

The €10,000 exemption applies per calendar year. Every sale and every swap before 31 December counts for 2026. FIFO across all your accounts determines which purchase you sell, and therefore how much capital gain you realise. According to the legal text, an unused exemption only carries over if you used less than €1,000. Buying back after a sale remains an open question, and many trades shortly before year-end can push you towards the speculative regime.

This article and the amounts in Cryptotax are an indicative calculation based on the published legal text and the transactions you have imported so far, not tax advice. Consult your accountant or tax adviser for your own situation.