Betting exchange explained
A betting exchange is a platform where punters bet against each other rather than against a bookmaker, with one side backing an outcome and the other laying it. The exchange matches the two offers, holds both stakes and takes its cut as commission on net winnings instead of building a margin into the odds. A bet only becomes live once someone on the other side accepts your price, which is why the odds you see depend on what other customers are willing to offer.
How is a lay bet calculated?
Laying means you take the bookmaker’s side: you win the backer’s stake if the selection fails, and you pay out their profit if it wins.
That payout is your liability, worked out as backer’s stake × (decimal odds – 1). Lay €10 at 3.00, which is 2/1 or an implied probability of 33.3%, and your liability is €20. If the selection loses you collect €10, less commission.
Commission is charged on your net result across the whole market, not bet by bet, and nothing is charged on a market you lose overall. Rates differ between exchanges and account packages; Betfair, for one, publishes packages for Irish customers at 2%, 5% and 8%. At 5%, that €10 lay win becomes €9.50.
Exchange or bookmaker: where the money goes
The exchange is most often confused with an ordinary sportsbook, though the two earn their money in different ways.
Betting exchange | Bookmaker |
|---|---|
| You can back or lay | You can only back |
| Fee is commission on net winnings | Margin built into every price |
| Odds set by other customers | Odds set by the trader |
| Bet may sit unmatched | Bet accepted at quoted price |
| Thin markets can lack liquidity | Prices offered on most markets |
| Fewer free bets and promotions | Free bets, often stake not returned |
Where Irish punters meet exchange odds
You mostly meet exchange prices on horse racing and football, where liquidity is deepest.
A bookmaker’s odds include an overround, so a two-runner market at 10/11 each adds up to about 104.8%. Exchange prices on busy markets sit much closer to 100%, but the commission still comes off your winnings, so compare both after costs.
