In this guide
Key difference: Spread betting profits carry no tax liability under UK law. Prediction market earnings (from decentralised platforms such as Polymarket) may trigger CGT or Income Tax obligations. For UKGC-authorised, tax-exempt event wagering, Betfair Exchange offers the nearest equivalent. For market depth and minimal charges, Polymarket accessed through PolyGram is superior.
If you trade in the UK, two primary avenues exist for generating returns through accurate outcome forecasting: spread betting (through FCA-licensed financial spread betting operators) and prediction markets (through Polymarket, Betfair Exchange, or Smarkets). Grasping these distinctions matters significantly for structuring your tax position and investment approach.
What Is Spread Betting in the UK?
The UK's financial spread betting sector comprises FCA-authorised providers including IG, CMC Markets, and Spreadex. You stake per-point movements on financial assets (FTSE 100, currency pairs, individual equities). Principal attributes include:
- Leverage: Ranges from 2:1 to 20:1 contingent on the underlying asset
- Tax-free profits: Spread betting holds gambling classification in UK law — winnings incur no tax, losses cannot offset income
- FCA regulated: Comprehensive investor safeguards, mandatory negative balance safeguards
- Markets: Financial instruments (indices, currency, raw materials, equities) — excludes political or athletic outcomes
- Bid-ask spread: Inherent transaction expense (normally 1–3 pips on major currency pairs)
What Are Prediction Markets?
Prediction markets enable you to acquire YES/NO binary contracts linked to tangible real-world events. Primary UK-available platforms include:
- Polymarket (via PolyGram): 8,400+ markets, USDC denominated, ~1% typical cost, regulatory ambiguity
- Betfair Exchange: 500 markets, sterling-based, 5% commission rate, UKGC authorised
- Smarkets: 200 markets, sterling-based, 2% commission rate, UKGC authorised
Tax Treatment — The Critical Difference
Spread Betting: Tax-Free
Spread betting returns are wholly excluded from both Capital Gains Tax and Income Tax in the UK when conducted through an FCA-licensed operator. This represents among the most advantageous tax provisions accessible to UK retail investors. HMRC's official position endorses this treatment for financial spread betting activity.
Betfair Exchange / Smarkets: Tax-Free
Winnings from UKGC-authorised betting exchanges receive identical tax treatment — classified as gambling proceeds under the Gambling Act 2005 framework. Consequently, Betfair and Smarkets merge prediction market functionality with unambiguous tax-free standing.
Polymarket: Tax Uncertain
Polymarket returns do not fit neatly within either the gambling exemption (lacks UKGC authorisation) or the spread betting exemption (not an FCA-authorised financial spread betting service). HMRC could potentially categorise them as CGT or Income Tax liabilities. Consult our comprehensive tax resource.
Comparison — Spread Betting vs Prediction Markets
| Factor | Spread Betting | Betfair/Smarkets | Polymarket (PolyGram) |
|---|---|---|---|
| UK Tax Status | Tax-free ✅ | Tax-free ✅ | Uncertain ⚠️ |
| Regulation | FCA ✅ | UKGC ✅ | Grey zone |
| Leverage | Up to 20:1 | None | None |
| Markets | Financial only | ~200–500 | 8,400+ |
| Max Profit | Unlimited (leveraged) | 2x (binary) | Up to 100x (low-prob YES) |
| Max Loss | Unlimited (leveraged) | Stake only | Stake only |
| GBP Deposits | Yes ✅ | Yes ✅ | Via crypto |
| Effective Costs | 1–3% spread | 2–5% | ~1% |
When to Use Spread Betting vs Prediction Markets
Choose Spread Betting When:
- You seek leveraged positions in financial instruments (FTSE 100, currency markets)
- Tax-free standing is paramount and regulatory certainty essential
- Your focus centres on financial price dynamics rather than discrete event outcomes
- You value FCA negative balance safeguards
Choose Prediction Markets When:
- You possess demonstrable skill in forecasting particular real-world events (referendums, athletics, scientific developments)
- You favour a bounded-loss, binary framework (maximum loss equals your wager)
- You need exposure to markets unavailable through spread betting (geopolitics, emerging tech, environmental)
- Cost efficiency relative to conventional bookmakers drives your decision-making
Best Combined Approach for UK Traders:
- Deploy an FCA-authorised spread betting account (IG, CMC) for financial instrument positions where leverage and tax exemption are strategically important
- Deploy Smarkets or Betfair Exchange for domestic politics and athletics — UKGC-authorised, tax-exempt, sterling-denominated
- Deploy Polymarket via PolyGram for niche markets absent elsewhere (8,000+ international event contracts) — acknowledging tax ambiguity or maintaining thorough documentation
FAQ — Spread Betting vs Prediction Markets UK
- Is Betfair Exchange classed as spread betting?
- No — Betfair Exchange operates as a betting exchange (UKGC-regulated), distinct from financial spread betting platforms (FCA-regulated). Both generate tax-free outcomes under separate UK regulatory frameworks. Betfair operates under gambling classification; spread betting falls under financial speculation — both exempt from tax, overseen by different authorities.
- Can spread betting firms offer political prediction markets?
- Certain providers do — IG Index and Spreadex facilitate election outcome spread bets (for instance, "Conservative seats at 200–210"). These winnings remain tax-free. Nevertheless, selection pales beside Polymarket's 249 UK-focused political contracts.
- Is there a UK prediction market with leverage?
- Not conventionally. Betfair and Smarkets employ binary mechanics (stake-only). Polymarket operates identically. For leveraged event exposure, financial spread betting represents the sole FCA-authorised mechanism — though it exclusively covers financial instrument pricing, excluding standalone event outcomes.