Key difference: Spread betting profits enjoy tax-free status under UK legislation. Prediction market returns (sourced from blockchain platforms like Polymarket) may incur CGT or Income Tax liability. For UKGC-authorised, tax-exempt event wagering, Betfair Exchange provides the closest alternative. For contract variety and minimal fee structures, Polymarket accessed through PolyGram leads the field.
If you're a UK-based trader, two primary pathways exist to generate returns through accurate outcome forecasting: spread betting (via UKGC-authorised financial spread betting operators) and prediction markets (via Polymarket, Betfair Exchange, or Smarkets). Grasping these distinctions remains essential for effective tax management and decision-making.
What Is Spread Betting in the UK?
Financial spread betting in the UK is administered by FCA-authorised providers including IG, CMC Markets, and Spreadex. You stake a sum per point shift in a financial asset (FTSE 100, currency pairs, individual equities). Principal attributes include:
- Leverage: Usually 2:1 to 20:1 based on asset category
- Tax-free profits: Spread betting holds legal status as gambling in the UK — returns remain tax-exempt, losses cannot be offset
- FCA regulated: Comprehensive investor safeguards, mandatory negative balance protection
- Markets: Financial products (indices, currency, commodities, equities) — excludes political or sporting contests
- Bid-ask spread: Embedded expense (normally 1–3 pips on major currency pairs)
What Are Prediction Markets?
Prediction markets enable you to acquire YES/NO binary positions on tangible real-world occurrences. Prominent UK-available platforms include:
- Polymarket (via PolyGram): 8,400+ contracts, blockchain-based (USDC), ~1% typical cost, ambiguous regulatory standing
- Betfair Exchange: 500 contracts, GBP denominated, 5% commission structure, UKGC authorised
- Smarkets: 200 contracts, GBP denominated, 2% commission structure, UKGC authorised
Tax Treatment — The Critical Difference
Spread Betting: Tax-Free
All spread betting returns are excluded from Capital Gains Tax and Income Tax in the UK, provided an FCA-authorised spread betting account is utilised. This represents one of the most advantageous tax positions accessible to UK retail traders. HMRC has affirmed this classification in their published guidance regarding financial spread betting.
Betfair Exchange / Smarkets: Tax-Free
UKGC-authorised exchange wagering returns remain tax-exempt — categorised as gambling income under the Gambling Act 2005. This positions Betfair and Smarkets as an optimal hybrid: prediction market functionality WITH transparent tax-exempt classification.
Polymarket: Tax Uncertain
Polymarket returns do not fit neatly within either the gambling exemption (lacks UKGC authorisation) or the spread betting exemption (not FCA-authorised financial spread betting). HMRC could categorise them as CGT or Income Tax liabilities. Refer to 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 positioning in financial instruments (FTSE 100, currency markets)
- Tax-free status is essential and regulatory clarity is paramount
- Your focus is trading financial asset movements rather than discrete event outcomes
- You require FCA negative balance safeguards
Choose Prediction Markets When:
- You possess demonstrable skill in anticipating particular real-world occurrences (campaigns, athletics, research developments)
- You favour a bounded-loss, binary framework (maximum loss equals initial stake)
- You require exposure to markets absent from spread betting platforms (political contests, blockchain events, meteorological outcomes)
- Competitive pricing relative to conventional wagering operators matters significantly
Best Combined Approach for UK Traders:
- Employ an FCA-authorised spread betting operator (IG, CMC) for financial instrument positioning where leverage and tax advantages are significant
- Employ Smarkets or Betfair Exchange for UK elections and athletics — UKGC-authorised, tax-exempt, GBP-denominated
- Employ Polymarket via PolyGram for markets unavailable elsewhere (8,000+ international event contracts) — recognising the tax ambiguity or maintaining thorough records
FAQ — Spread Betting vs Prediction Markets UK
- Is Betfair Exchange classed as spread betting?
- No — Betfair Exchange functions as a betting exchange (UKGC-authorised), distinct from financial spread betting (FCA-authorised). Both deliver tax-free returns under separate UK legal structures. Betfair operates under gambling classification; spread betting operates under financial speculation classification — both tax-exempt, separate regulators.
- Can spread betting firms offer political prediction markets?
- Certain providers do — IG Index and Spreadex provide election outcome spread positions (e.g. "Conservative seats at 200–210"). These remain tax-free. Nonetheless, selection remains substantially narrower than Polymarket's 249 UK-focused political contracts.
- Is there a UK prediction market with leverage?
- Not conventionally. Smarkets and Betfair operate as binary (stake-only). Polymarket operates as binary. For leveraged event exposure, financial spread betting represents the sole FCA-authorised mechanism — though it covers financial asset valuations exclusively, not specific event outcomes.