Polymarket in Belgium: Gambling, crypto or taxable income? 

Prediction markets have rapidly become a notable development within the online gambling and crypto world. On platforms such as Polymarket, users can speculate on future events, such as elections, sports matches, interest rate decisions or geopolitical developments. 

For Belgian users, the question is not merely whether a profit can be made. The more important question is: how does Belgium view this type of platform? Is it a form of gambling, trading in crypto-assets, or taxable income? 

Is Polymarket a form of gambling in Belgium? 

In Belgium, the initial assessment does not lie with the tax authorities, but with the Gaming Commission. It oversees compliance with the Belgian Gaming Act. 

Polymarket does not hold a Belgian gambling licence. As a result, the platform is not regarded in Belgium as a standard financial or crypto service, but as an unlicensed gambling offering. Polymarket has been on Belgium’s blacklist of illegal gambling sites since 2025. 

This is important. In Belgium, a provider cannot simply target Belgian players without a licence. Even when a platform operates using crypto, smart contracts or prediction markets, this principle does not automatically change. 

Do Belgian players have to pay tax on Polymarket winnings? 

The situation in Belgium differs from that in the Netherlands. In the Netherlands, gambling tax has a much more direct impact on players. In Belgium, tax on gambling and betting is, in principle, levied on the organiser or intermediary who accepts stakes. 

For an ordinary Belgian player, this does not automatically mean that any winnings from gambling or betting are directly subject to personal income tax. Occasional winnings from games of chance are not generally treated as professional income in Belgium. 

However, with Polymarket, the situation is more complicated. The platform is not licensed in Belgium and operates with crypto-assets, usually USDC. This can give rise to several questions: 

• Are the profits the result of a game of chance? 

• Do the profits stem from trading in contract positions? 

• Is trading carried out as a private individual or in a professional capacity? 

• Are trading bots, arbitrage or automated strategies used? 

• Is this an occasional profit or a regular source of income? 

For ordinary, occasional users, the tax authorities are unlikely to classify this as professional income. However, in the case of large volumes, systematic trading or automated strategies, the situation may be different 

When might the Belgian tax authorities take an interest? 

The Belgian tax authorities focus primarily on the nature of the activity. Someone who occasionally takes a position on a prediction market is in a different situation to someone who trades daily, uses software, exploits market imperfections or deals in large sums. 

If the activity is carried out professionally or in an organised manner, profits may be regarded as professional income. In that case, they are taxed according to the standard progressive rates under personal income tax. 

In addition, Belgium also has a category for miscellaneous income. This may be relevant when profits fall outside the normal management of private assets but do not yet constitute a genuine professional activity. 

In other words: it is not just a question of how much someone earns, but above all how that profit is generated. 

Trading bots change the picture 

The use of trading bots makes the discussion more sensitive. A bot that automatically opens and closes positions, exploits price differences or trades day and night, resembles less a random gamble and more an organised trading activity. 

In such cases, the tax authorities may be quicker to argue that a structural advantage exists. This is certainly the case when the user employs knowledge, technology, data analysis or their own software to make profits systematically. 

For Belgian users, this means that trading bots increase the risk of such income being classified for tax purposes as professional income or miscellaneous income. This is certainly the case when large volumes or repeated transactions are involved. 

Crypto and USDC remain a separate point of attention 

Polymarket operates using USDC, a stablecoin. For Belgium, this means that users must also take into account the tax treatment of crypto assets. 

Furthermore, from 2026, a new capital gains tax on financial assets will be introduced in Belgium, with cryptocurrencies included among the examples. Whether and how Polymarket positions fall under this will depend on the specific circumstances. 

In addition, from 2026, DAC8 will ensure greater automatic exchange of data on crypto assets within Europe. Crypto service providers will be required to collect and report customer and transaction data. This will make it easier for tax authorities to gain an overview of crypto activities. 

Can this be done through a company? 

For professional users or parties working with trading bots, the question may arise as to whether it is better to conduct the activity through a company. 

This may offer tax and administrative advantages, but it does not solve everything. The regulatory question remains: is a Belgian user or a Belgian company permitted to participate in a platform that is considered an illegal gambling service in Belgium?  

A company does not, therefore, automatically alter Belgian gambling law. Even in such cases, consideration must be given to the place of business, the tax domicile, the nature of the income and whether participation in the platform is legally permitted. 

Polymarket in Belgium: a sensitive grey area 

In Belgium, Polymarket operates in a sensitive grey area where gambling, cryptocurrency and taxation intersect. The key point is that Polymarket is not licensed in Belgium and is treated by the Gaming Commission as an illegal gambling service. 

For occasional users, the tax implications will often be limited. However, as soon as large sums of money, regular trading, trading bots or professional strategies are involved, there is a greater risk that the Belgian tax authorities will treat the proceeds as taxable income. 

The key question then shifts from ‘do I have to pay tax on a profit?’ to ‘how is this activity classified for legal and tax purposes in Belgium?’