Key difference: Spread betting earnings remain untaxed under UK legislation. Prediction market returns (from decentralised platforms such as Polymarket) may face Capital Gains Tax or Income Tax liability. For UKGC-authorised, tax-exempt event wagering, Betfair Exchange provides the nearest equivalent. For market depth and competitive fee structures, Polymarket accessed through PolyGram leads the field.
If you trade in the United Kingdom, you have two primary pathways to generate returns from accurate event forecasting: spread betting (through FCA-licensed financial spread betting operators) and prediction markets (via Polymarket, Betfair Exchange, or Smarkets). Grasping these distinctions proves essential for structuring your tax obligations and trading approach.
What Is Spread Betting in the UK?
The UK market for financial spread betting comprises FCA-authorised providers including IG, CMC Markets, and Spreadex. Participants wager a per-point stake on price movements in financial assets (FTSE 100, currency pairs, individual equities). Core attributes include:
- Leverage: Commonly ranges from 2:1 to 20:1 based on underlying asset category
- Tax-free profits: Spread betting receives legal treatment as gambling in the UK — returns incur no tax, and losses cannot be claimed as deductions
- FCA regulated: Comprehensive investor safeguards, mandatory negative balance protection
- Markets: Financial instruments (indices, currency markets, raw materials, equities) — excludes political or athletic outcomes
- Bid-ask spread: Embedded cost structure (usually 1–3 pips for major currency pairs)
What Are Prediction Markets?
Prediction markets enable traders to acquire YES/NO binary contracts referencing actual events. Primary UK-available platforms include:
- Polymarket (via PolyGram): 8,400+ markets, USDC denomination, ~1% effective fee, legally ambiguous status
- Betfair Exchange: 500 markets, Sterling-denominated, 5% commission, UKGC authorised
- Smarkets: 200 markets, Sterling-denominated, 2% commission, UKGC authorised
Tax Treatment — The Critical Difference
Spread Betting: Tax-Free
All spread betting returns are exempt from both Capital Gains Tax and Income Tax in the United Kingdom, provided your account sits with an FCA-authorised spread betting provider. This represents one of the most substantial tax benefits accessible to UK private traders. HMRC has formally documented this classification regarding financial spread betting arrangements.
Betfair Exchange / Smarkets: Tax-Free
Winnings from UKGC-authorised betting exchange transactions likewise enjoy tax-exempt treatment — classified as gambling income under the Gambling Act 2005. Consequently, Betfair and Smarkets deliver an optimal combination: prediction market functionality alongside transparent tax-exempt standing.
Polymarket: Tax Uncertain
Polymarket returns do not neatly align with either the gambling exemption (lacking UKGC authorisation) or the spread betting exemption (not an FCA-authorised financial spread betting service). HMRC could potentially classify them as Capital Gains Tax or Income Tax obligations. Consult our regulatory guidance for additional clarity.
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 require leveraged positions in financial instruments (FTSE 100, currency pairs)
- Tax-exempt status represents a core requirement and regulatory certainty matters most
- Your trading focuses on financial price fluctuations rather than discrete event outcomes
- You value FCA negative balance safeguards
Choose Prediction Markets When:
- You possess demonstrable skill in forecasting particular real-world occurrences (political contests, athletic competitions, scientific developments)
- You prefer a bounded-loss, binary framework (maximum loss equals your initial stake)
- You seek exposure to markets absent from spread betting offerings (geopolitical events, blockchain developments, meteorological contracts)
- Minimising costs relative to conventional betting operators constitutes a strategic priority
Best Combined Approach for UK Traders:
- Deploy an FCA-regulated spread betting account (IG, CMC) for financial instrument positions where leverage and tax-exempt treatment align with your objectives
- Employ Smarkets or Betfair Exchange for domestic political and athletic markets — UKGC-authorised, tax-exempt, Sterling-based
- Access Polymarket via PolyGram for specialised markets unavailable elsewhere (8,000+ international event contracts) — acknowledging the 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-authorised), distinct from financial spread betting platforms (FCA-authorised). Both deliver tax-exempt returns under separate UK regulatory frameworks. Betfair falls under gambling classification; spread betting constitutes financial speculation — both tax-exempt, overseen by different authorities.
- Can spread betting firms offer political prediction markets?
- Certain providers do — IG Index and Spreadex facilitate election outcome spread bets (e.g. "Conservative seats at 200–210"). These transactions remain tax-exempt. Nevertheless, selection remains substantially narrower than Polymarket's 249 UK-focused political contracts.
- Is there a UK prediction market with leverage?
- Not conventionally. Betfair and Smarkets operate on binary terms (stake-only). Polymarket follows the same binary structure. Leveraged event trading through FCA-regulated mechanisms remains confined to financial spread betting — though this covers financial instrument pricing exclusively, not discrete event outcomes.