How it works, and the risks

An arbitrage ("arb") exists when the best prices for every outcome of a market, taken across different bookmakers and exchanges, add up to an implied probability below 100 percent. Backing every outcome at the right stakes then returns the same amount whichever result happens.

What ArbHound does

It compares the prices it holds, removes exchange commission, ignores prices older than your staleness limit, works out the stake for each leg and shows the profit under each outcome. It never places a bet. You decide, you place each bet yourself, and you record what you actually got.

Why a "sure thing" is not always sure

• Prices move. A price can change before you place the second leg.
• Non-runners. A withdrawn horse can trigger deductions that remove the margin.
• Dead heats. Stakes are split and your return falls.
• Rule differences. Venues can settle or void markets differently.
• Account restrictions. Bookmakers may limit or close accounts that take arbs.
• Exchange liquidity. Your bet may only part match.

Staying in control

You can pause ArbHound from Settings. An active pause cannot be shortened. If gambling is causing you harm, free, confidential help is available from GamCare (0808 8020 133), BeGambleAware and GAMSTOP for UK self-exclusion.

ArbHound is for people aged 18 and over. It is not tax, financial or legal advice, and it does not offer tips.