In this guide
Key difference: Spread betting winnings enjoy tax-free status under UK law. Prediction market returns (from blockchain platforms such as Polymarket) may face CGT or Income Tax liability. For UKGC-authorised, tax-exempt event wagering, Betfair Exchange provides closer parity. For market depth and minimal charges, Polymarket accessed via PolyGram leads.
As a British trader, you have two primary pathways to capitalise on accurate outcome forecasting: spread betting (through FCA-authorised financial spread betting operators) and prediction markets (via Polymarket, Betfair Exchange, or Smarkets). Grasping these distinctions proves essential for structuring tax obligations and refining trading methodology.
What Is Spread Betting in the UK?
Financial spread betting across the UK is delivered by FCA-regulated entities including IG, CMC Markets, and Spreadex. You stake a sum per point shift in a financial asset (FTSE 100, currency pairs, individual equities). Essential attributes:
- Leverage: Commonly 2:1 through 20:1 contingent on asset category
- Tax-free profits: Spread betting receives legal classification as gambling in the UK — returns are tax-exempt, losses cannot be offset
- FCA regulated: Comprehensive investor safeguards, mandatory negative balance safeguards
- Markets: Financial assets (indices, currency, raw materials, equities) — excludes political or athletic outcomes
- Bid-ask spread: Embedded expense (usually 1–3 pips on primary currency pairs)
What Are Prediction Markets?
Prediction markets enable you to purchase YES/NO derivative contracts tied to tangible real-world events. Primary UK-accessible alternatives:
- Polymarket (via PolyGram): 8,400+ contracts, blockchain-based (USDC), ~1% typical charge, legally ambiguous
- Betfair Exchange: 500 contracts, Sterling, 5% commission, UKGC authorised
- Smarkets: 200 contracts, Sterling, 2% commission, UKGC authorised
Tax Treatment — The Critical Difference
Spread Betting: Tax-Free
Every spread betting return is exempt from Capital Gains Tax and Income Tax in the UK, provided you operate through an FCA-licensed spread betting facility. This represents one of the most advantageous tax provisions accessible to UK private traders. HMRC has substantiated this stance within their financial spread betting documentation.
Betfair Exchange / Smarkets: Tax-Free
UKGC-authorised betting exchange returns are likewise tax-exempt — categorised as gambling revenue under the Gambling Act 2005. This positions Betfair and Smarkets as the optimal hybrid: prediction market functionality PLUS unambiguous tax-exempt classification.
Polymarket: Tax Uncertain
Polymarket returns do not align neatly with either the gambling exemption (absent UKGC authorisation) or the spread betting exemption (lacks FCA-authorised financial spread betting status). HMRC could categorise them as CGT or Income Tax liabilities. Refer to our comprehensive tax guidance.
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 positioning in financial instruments (FTSE 100, currency)
- Tax-free standing is paramount and regulatory clarity is essential
- You're analysing financial price fluctuations rather than discrete occurrences
- You require FCA negative balance safeguards
Choose Prediction Markets When:
- You possess analytical advantage in anticipating particular real-world occurrences (referendums, athletic contests, technological breakthroughs)
- You favour a bounded-loss, binary structure (maximum loss equals initial stake)
- You require entry to outcome markets unavailable through spread betting (governmental, blockchain-based, meteorological)
- Reduced commissions relative to conventional operators matter significantly
Best Combined Approach for UK Traders:
- Deploy an FCA-regulated spread betting facility (IG, CMC) for financial instrument access where leverage and tax exemption are priorities
- Deploy Smarkets or Betfair Exchange for UK political outcomes and athletics — UKGC-authorised, tax-exempt, Sterling-denominated
- Deploy Polymarket via PolyGram for contracts absent from other venues (8,000+ international event derivatives) — recognising tax ambiguity or maintaining thorough records
FAQ — Spread Betting vs Prediction Markets UK
- Is Betfair Exchange classed as spread betting?
- No — Betfair Exchange operates as a betting exchange (UKGC-authorised), distinct from financial spread betting platforms (FCA-authorised). Both deliver tax-exempt returns via separate UK regulatory structures. Betfair falls under gambling classification; spread betting falls under financial speculation — both tax-exempt, distinct supervisory bodies.
- Can spread betting firms offer political prediction markets?
- Certain providers do — IG Index and Spreadex furnish electoral outcome spread positions (e.g. "Conservative representation at 200–210"). These carry tax-free standing. Nevertheless, breadth remains substantially constrained relative to Polymarket's 249 UK-centric electoral contracts.
- Is there a UK prediction market with leverage?
- Not conventionally. Betfair and Smarkets operate as binary (stake-only). Polymarket functions as binary. For leveraged occurrence trading, financial spread betting constitutes the sole FCA-authorised mechanism — though restricted to financial instrument pricing, excluding discrete occurrence outcomes.