Is Polymarket UK Legal? Tax & Regulation Guide

Is Polymarket Legal for UK Users?

The short answer: yes, you can legally use Polymarket as a UK resident, but with important caveats.

Polymarket is a decentralised prediction market platform built on blockchain technology. It is not authorised by the UK Financial Conduct Authority (FCA), nor does it hold a betting licence from the Gambling Commission. This is a crucial distinction. Unlike traditional UK bookmakers or betting exchanges, Polymarket operates outside the standard UK regulatory framework.

However, this does not automatically make it illegal for UK residents to use. The FCA's regulatory perimeter does not extend to all financial activities, particularly those involving decentralised finance (DeFi) and peer-to-peer prediction markets. The platform itself does not require FCA authorisation to exist; rather, any UK-based entity offering regulated financial services would need approval.

Polymarket's terms of service explicitly restrict access from certain jurisdictions, but the UK is not among them as of 2026. The platform is accessible to UK users, though this remains an area where regulation could tighten. The legal position is therefore one of permitted but unregulated—a status that carries both freedom and responsibility.

The critical obligation falls on you: as a UK resident, you must comply with tax law and report any profits to HM Revenue & Customs (HMRC). Failure to do so is tax evasion, which carries criminal penalties.

How HMRC Classifies Prediction Market Gains

This is where the legal picture becomes murky. HMRC has not issued specific guidance on prediction markets like Polymarket, which creates genuine uncertainty for traders.

Broadly, HMRC may classify your activity in one of three ways:

• Gambling winnings (tax-free): If HMRC treats prediction markets as gambling, winnings are not taxable. This is the most favourable outcome for traders. Gambling losses are also not tax-deductible.
• Trading income (fully taxable): If you are deemed to be trading—particularly if you trade frequently, systematically, and with the intention of making a profit—gains are taxed as income at your marginal rate (20–45% depending on your tax band). Losses can be offset against income.
• Capital gains (partially taxable): If you hold positions as investments rather than trading them actively, gains may be subject to capital gains tax (20% for higher earners, 10% for basic-rate taxpayers, with an annual exemption of £3,000 in 2026). Losses can be offset against other capital gains.

The classification depends on several factors: frequency of trading, holding periods, whether you trade for income or investment, the proportion of your income derived from trading, and whether you advertise yourself as a trader. Someone who places a few bets per year is more likely to be treated as a gambler; someone trading daily across multiple markets is more likely to be treated as a trader.

In practice, HMRC's approach to DeFi and blockchain-based activities remains evolving. The tax authority has issued guidance on cryptocurrency but has not definitively ruled on prediction markets. This ambiguity is a real risk: HMRC could challenge your classification if you are audited, and the burden of proof falls partly on you to demonstrate your position.

Registration and Reporting Requirements

If you are classified as a trader, you must register for Self Assessment with HMRC if you are not already registered. This is a legal requirement if your trading income exceeds the threshold (currently £1,000 per tax year, though this is subject to change).

You must then file a Self Assessment tax return each year, reporting:

• Total trading income from prediction markets
• Any losses incurred
• Expenses directly related to your trading activity (e.g., software subscriptions, research materials, accountancy fees)

Record-keeping is essential. You should maintain detailed records of:

• Every trade: date, market, stake, outcome, and profit or loss
• Exchange rates if you are trading in USD or other currencies (Polymarket operates primarily in USDC, a stablecoin)
• Any fees paid to the platform
• Withdrawal dates and amounts

Most prediction market traders use spreadsheets or dedicated crypto tax software to track this. Services like Koinly or CoinTracker can integrate with blockchain wallets and generate reports suitable for HMRC submission, though they require accurate initial setup.

If you are treated as a gambler, no Self Assessment registration is required, and you do not need to report winnings. However, if HMRC later disputes this classification, you will have no documentation to support your position—a significant risk.

The Regulatory Grey Zone and Future Risk

Polymarket's legal status in the UK is not settled. The platform operates in a regulatory gap, which creates both opportunity and risk.

Currently, the FCA does not have direct authority over Polymarket because it is not an FCA-regulated entity. However, the FCA has been increasingly focused on cryptocurrency and DeFi activities. In January 2026, the FCA published updated guidance on cryptoassets, and prediction markets could fall within future regulatory scope.

Several regulatory developments could affect UK users:

• FCA authorisation requirements: The FCA could require platforms offering prediction markets to UK users to obtain authorisation. This would likely force Polymarket to either comply or restrict UK access.
• Gambling Commission oversight: If prediction markets are classified as gambling, the Gambling Commission could require operators to hold a licence. Polymarket does not currently hold one.
• Tax authority crackdowns: HMRC could issue definitive guidance on prediction markets, potentially reclassifying all such activity as taxable income rather than gambling.
• Sanctions and restrictions: The UK could impose sanctions on decentralised platforms, particularly if they are used for money laundering or sanctions evasion.

The risk is real but not imminent. Polymarket has been operating globally since 2020 and has not been shut down in major jurisdictions. However, regulatory action could happen with little warning, and retroactive tax assessments are possible.

Tax Planning and Professional Advice

If you are a serious prediction market trader, tax planning is essential.

First, consider whether you should formally register as a trader. If you trade frequently and systematically, registration may actually benefit you by allowing you to claim expenses and losses. If you trade occasionally, you might argue for gambling treatment, which is tax-free but offers no loss relief.

Second, keep meticulous records from day one. This is non-negotiable. If HMRC audits you, poor documentation will count against you.

Third, consider the timing of gains and losses. If you realise large gains in one tax year, you might defer closing other positions until the next tax year to spread your tax liability. This is legitimate tax planning, not evasion.

Fourth, consult a tax professional who understands cryptocurrency and DeFi. A good accountant can help you:

• Determine the appropriate tax classification for your activity
• Calculate your tax liability accurately
• Identify legitimate expenses and deductions
• Prepare documentation for HMRC if audited
• Plan for future tax years

The cost of professional advice (typically £500–2,000 per year for a small trader) is usually far less than the cost of getting it wrong with HMRC.

Practical Steps to Stay Compliant

Here is a practical checklist for UK users of Polymarket:

• Register for Self Assessment: If you expect trading income to exceed £1,000 per tax year, register with HMRC immediately. Registration takes about 10 minutes online.
• Use tax software: Set up a crypto tax tool or spreadsheet to track all trades in real time. Do not rely on memory or bank statements alone.
• Document your intent: Keep records showing whether you trade for income or investment. This supports your tax classification if challenged.
• Report honestly: File your Self Assessment return on time and accurately. Late filing and dishonest reporting carry penalties.
• Keep receipts: Save copies of platform statements, withdrawal confirmations, and any correspondence with Polymarket.
• Consult a professional: If your trading activity is significant (e.g., more than £10,000 per year), hire a tax accountant.
• Monitor regulatory news: Follow FCA and HMRC announcements about cryptocurrency and prediction markets. Regulation could change quickly.

Frequently Asked Questions

Is Polymarket licensed in the UK?

No. Polymarket is not authorised by the FCA or licensed by the Gambling Commission. It operates as an unregulated platform.

Could I face criminal charges for using Polymarket?

Using Polymarket itself is not a criminal offence. However, failing to report taxable gains to HMRC is tax evasion, which is a crime. The risk is tax-related, not criminal prosecution for using the platform.

What happens if I do not report my Polymarket gains?

If HMRC discovers unreported gains through an audit or data-sharing agreement (which increasingly happens with financial institutions), you could face:

• Back taxes owed with interest
• Penalties of 20–100% of the unpaid tax, depending on the severity
• Criminal prosecution if the amount is large or the evasion deliberate

Are my funds protected if Polymarket fails?

No. Polymarket is not regulated by the FCA, so your funds are not covered by the FSCS. If the platform is hacked, shut down, or becomes insolvent, you have no statutory protection and limited recourse.

What if HMRC has not issued guidance on prediction markets?

The absence of guidance does not mean you can ignore tax obligations. You are still legally required to report taxable income. If audited, HMRC will assess your activity based on established tax principles, and you will need to justify your position. Professional advice is highly recommended.

Can I claim losses against other income?

If you are classified as a trader, yes—losses can be offset against other trading income or, in some cases, carried back or forward. If you are classified as a gambler, losses are not deductible. This is another reason to keep detailed records and consider professional classification.

Conclusion: Legal but Risky

Polymarket is legal for UK residents to use, but it operates in a regulatory grey zone. You can trade on the platform without breaking the law, provided you comply with tax obligations. The real risks are tax-related: misclassification, unreported gains, poor record-keeping, and potential future regulatory changes.

The platform itself carries financial risk—your funds are unprotected, and you could lose your entire stake. The legal and tax landscape is also uncertain and could change.

If you decide to use Polymarket, do so with eyes open. Keep meticulous records, report all gains to HMRC, and consider professional advice if your activity is significant. This approach protects you legally and minimises the risk of costly disputes with the tax authority.

For more detailed information about prediction markets and how they compare to other betting platforms, visit Polymarket UK.