Is Polymarket Legal in the UK? Tax Status Explained

The Current Legal Status of Polymarket in the UK

Polymarket, the decentralised prediction market platform built on blockchain technology, operates without explicit FCA authorisation in the United Kingdom. This does not automatically make it illegal, but it does create significant regulatory uncertainty for UK users. The platform allows participants to buy and sell shares in the outcome of real-world events—from political elections to scientific breakthroughs—and settle trades in USDC (a stablecoin pegged to the US dollar).

The FCA's current stance is that Polymarket does not fall neatly into any of its regulated categories. It is not classified as a betting exchange (which would require specific licensing), nor is it regulated as an investment platform or financial services firm. This absence of regulation does not mean the platform is legal or illegal; rather, it exists outside the formal regulatory perimeter. UK residents can technically access Polymarket, but doing so carries legal and tax compliance risks that users must understand.

The regulatory position differs markedly from traditional betting exchanges or spread-betting firms, which must be FCA-authorised to operate legally in the UK. Polymarket's decentralised nature and offshore incorporation make it difficult for UK authorities to enforce direct oversight. However, this does not shield UK users from their own tax and legal obligations.

FCA Regulation and What It Means for Polymarket Users

The Financial Conduct Authority does not currently regulate Polymarket directly. This is a crucial distinction: the absence of FCA regulation does not confer legal protection on users. If you trade on Polymarket and lose money, you will not be covered by the Financial Services Compensation Scheme (FSCS), which protects customers of regulated firms up to £85,000 per claim.

The FCA has issued warnings about unregulated crypto platforms and decentralised finance (DeFi) applications, emphasising that consumers who use them do so at their own risk. Polymarket, whilst not explicitly named in recent FCA guidance, falls within this broader category of unregulated platforms. The regulator has made clear that it cannot guarantee the safety of funds held on such platforms, nor can it intervene if a platform fails, is hacked, or becomes insolvent.

In 2026, the FCA's regulatory framework continues to evolve, particularly around crypto assets and digital finance. The Financial Services and Markets Bill (now progressing through Parliament) may introduce new rules for certain crypto activities, but Polymarket's current status remains unresolved. Users should not assume that regulatory clarity will emerge quickly or in their favour.

One important point: using an unregulated platform does not exempt you from UK tax law. In fact, the reverse is true. HMRC expects all UK residents to declare income and gains from all sources, regardless of whether those sources are regulated or unregulated.

Tax Classification: Is Polymarket Trading Gambling, Investment, or Speculation?

The tax treatment of Polymarket gains hinges on how HMRC classifies your activity. This is not a binary question with a single correct answer; it depends on the facts of your individual case. HMRC uses several tests to determine whether activity constitutes gambling, investment, or trading.

The Gambling Classification

If HMRC deems your Polymarket activity to be gambling, winnings are generally not taxable as income under UK tax law. This is a significant advantage, because gambling winnings are exempt from income tax. However, this exemption comes with important caveats. First, if you are a professional gambler or betting exchange operator, different rules apply, and you may face income tax on your profits. Second, the gambling exemption does not protect you from capital gains tax if you have made substantial gains that could be viewed as capital profits rather than gambling winnings.

HMRC's definition of gambling is broad and includes betting on events where the outcome is uncertain. Polymarket markets do fit this description superficially. However, HMRC has also stated that systematic, organised prediction-market activity—particularly if undertaken with a view to profit—may not qualify as mere gambling and could instead be classified as trading or investment activity.

The Trading Classification

If HMRC classifies your Polymarket activity as trading, all profits become taxable as trading income. This is typically the most onerous tax treatment. Trading income is subject to income tax at rates up to 45% (plus National Insurance contributions if you are self-employed), and you must also account for any losses you incur. Trading status is more likely to be assigned if you:

• Trade frequently and systematically on Polymarket
• Use sophisticated strategies or algorithms to identify profitable markets
• Treat Polymarket trading as your primary source of income or a significant secondary income
• Maintain detailed records and engage in active portfolio management
• Spend substantial time researching and executing trades

If HMRC determines that you are a trader, you must register for self-assessment and file a tax return each year. Failure to do so can result in penalties ranging from £100 to £3,000 or more, depending on the seriousness of the breach.

The Investment Classification

If your Polymarket activity is classified as investment, gains would typically be subject to capital gains tax (CGT). The UK capital gains tax rate is 10% for basic-rate taxpayers and 20% for higher-rate taxpayers, with an annual exemption of £3,000 (as of 2026). This is generally more favourable than trading income tax but less favourable than the gambling exemption.

Investment classification is more likely if you hold positions for longer periods, do not trade frequently, and treat Polymarket as a long-term wealth-building vehicle rather than an active income source. However, the line between investment and trading is not always clear, and HMRC will examine the substance of your activity, not merely the label you assign to it.

Practical Tax Reporting Obligations for UK Polymarket Users

Regardless of how your activity is classified, you must report it to HMRC if you are a UK tax resident. This is a legal obligation, and ignorance is not a defence. Here is what you need to do:

Self-Assessment Tax Return

If your Polymarket gains exceed the threshold for self-assessment (currently £1,000 of gross income from self-employment or trading), you must register for self-assessment and file a tax return. Even if your gains fall below this threshold, you must still report them if you have any other tax liability or if HMRC requests a return.

When filing, you should declare Polymarket gains in the appropriate section of the tax return. If you believe the gains are gambling winnings, you may not need to report them (though it is advisable to keep records in case HMRC questions your classification). If you believe they are trading income or investment gains, you must report them in the relevant section and pay any tax due by the deadline (typically 31 January following the tax year).

Record Keeping

HMRC requires you to keep records of all transactions for at least six years. For Polymarket, this means you should maintain:

• Screenshots or exports of all buy and sell orders, including dates, amounts, and prices
• Records of any deposits and withdrawals from your Polymarket account
• Conversion rates if you converted between GBP and USDC or other currencies
• Documentation of how you calculated your gains or losses
• Any correspondence with Polymarket support or other evidence of your account activity

Polymarket does not currently provide tax reporting documents (such as 1099 forms in the US context), so you will need to compile this information yourself. This is a significant administrative burden, but it is essential for compliance.

Currency Conversion and Reporting

Because Polymarket operates in USDC and other cryptocurrencies, you must account for currency gains and losses when converting to GBP. If you bought USDC at one exchange rate and sold it at another, the difference may constitute a separate taxable gain or loss. This complicates your tax position and requires careful record-keeping.

Risk Factors and Compliance Warnings

Several real risks accompany Polymarket use in the UK:

Regulatory Risk

The FCA or other UK authorities could take action against Polymarket or its UK users in the future. Whilst this is not imminent, the regulatory landscape for crypto and prediction markets is evolving rapidly. If the FCA were to declare Polymarket illegal for UK residents, users could face enforcement action, and any gains made on the platform could be subject to confiscation or penalty.

Tax Authority Challenges

HMRC has become increasingly active in pursuing tax evasion and avoidance, particularly in the crypto space. If you have not reported Polymarket gains, HMRC may discover your activity through platform data-sharing agreements, bank records, or other investigative means. The penalties for late reporting or underreporting can exceed the tax liability itself, particularly if HMRC deems the failure deliberate.

Platform Risk

Polymarket is a decentralised platform, but it still depends on various infrastructure components, including the Polygon blockchain, stablecoin issuers, and exchange liquidity providers. If any of these components fail, your ability to withdraw funds could be compromised. Additionally, if you lose access to your private keys or your account is compromised, there is no customer support mechanism to recover your funds.

Market Risk

Prediction markets are inherently volatile. Prices can move dramatically based on new information, sentiment shifts, or low liquidity. Unlike traditional betting, where your maximum loss is your stake, some prediction market structures can result in losses exceeding your initial investment if you are using leverage or complex strategies.

What HMRC Expects: Current Guidance and Future Developments

HMRC has not issued specific guidance on Polymarket or similar decentralised prediction markets. However, the tax authority has published general guidance on crypto assets and gambling that is relevant. HMRC's position is that:

• Gambling winnings are not taxable, but the burden is on the individual to demonstrate that their activity is genuinely gambling and not trading or investment
• Crypto assets are subject to capital gains tax, and transactions in crypto are treated as disposals for CGT purposes
• Trading in crypto or other assets is subject to income tax if it constitutes a trade
• All income and gains must be reported, regardless of whether the source is regulated or unregulated

In 2026, HMRC continues to develop its approach to crypto taxation. The Office of Tax Simplification has recommended clearer rules for crypto assets, and there is a possibility that statutory guidance specific to prediction markets and decentralised finance will emerge. Until then, users must make reasonable judgments about their tax position and be prepared to justify those judgments to HMRC if challenged.

Frequently Asked Questions

Can I Use Polymarket Legally in the UK?

Technically, yes, you can access and use Polymarket as a UK resident. The platform is not explicitly prohibited. However, you must comply with UK tax law, and you have no regulatory protection. The legality of using the platform itself is not in question; your tax compliance obligations are.

Do I Have to Pay Tax on Polymarket Gains?

Almost certainly, yes. The only exception would be if HMRC accepts that your activity constitutes gambling, in which case winnings are not taxable. However, this is not automatic, and HMRC may challenge your classification. You should assume that you will owe tax and plan accordingly.

What if I Don't Report My Polymarket Gains?

Not reporting is tax evasion, which is a criminal offence. HMRC can pursue you for unpaid tax, interest, and penalties. Penalties can range from 20% to 100% of the unpaid tax, depending on the seriousness of the breach. Additionally, if HMRC detects a pattern of non-reporting, it may investigate you for money laundering or other offences.

Is Polymarket Safer Than Traditional Betting Exchanges?

No. Traditional betting exchanges are FCA-regulated and offer FSCS protection. Polymarket offers neither. Your funds on Polymarket are at greater risk than on a regulated platform.

Should I Report My Polymarket Activity as Gambling or Trading?

This depends on the facts of your case. If you trade infrequently, hold positions for long periods, and do not treat Polymarket as a primary income source, gambling or investment classification may be more defensible. If you trade frequently and systematically, trading classification is more likely. You should consult a tax advisor to determine the most appropriate classification for your specific circumstances.

What Records Should I Keep?

Keep all transaction records, including dates, amounts, prices, and any currency conversions. Maintain these records for at least six years. Additionally, keep records of your reasoning for classifying your activity as gambling, trading, or investment, in case HMRC challenges your position.

Conclusion and Next Steps

Polymarket operates in a legal and regulatory grey area in the UK. Whilst the platform itself is not prohibited, it is unregulated and offers no consumer protection. More importantly, UK users must comply with tax law, and the tax treatment of Polymarket gains is uncertain. The safest approach is to assume that you will owe tax, maintain detailed records, and consult a qualified tax advisor before engaging in substantial trading.

If you are considering using Polymarket, weigh the potential rewards against the regulatory, tax, and financial risks. If you are already using the platform, prioritise tax compliance and record-keeping to minimise your exposure to penalties and enforcement action.

For more detailed guidance on prediction market taxation and regulatory developments in the UK, visit Polymarket Tax UK.