The maximum amount a layer (exchange bettor or bookmaker) could lose on a bet — the opposite of the backer's potential profit.
When you lay a bet on an exchange, you are acting as the bookmaker. If the selection wins, you must pay out the backer's profit. Your liability is the maximum amount you would owe: Liability = Backer's stake × (Lay odds − 1). If you lay £10 at 5.0, your liability is £10 × 4 = £40. You receive £10 in premium if the bet loses.
Exchanges require you to have sufficient funds to cover your liability before accepting a lay bet. The exchange holds this money in escrow. If the selection wins, it is paid to the backer. If it loses, the £10 is released to you as your profit.
Controlling liability is the core risk management task in exchange trading. A lay bet at 10.0 with £10 stake creates a £90 liability — nine times your potential profit. This is why value lays at low odds (1.5–2.5) are significantly safer in liability terms than lays at higher odds, even if the absolute edge is similar.
Lay Bet
Betting that an outcome will NOT happen — acting as the bookmaker on an exchange, collecting the stake if the selection loses and paying the liability if it wins.
Matched Betting
A technique that uses back and lay bets to extract guaranteed profit from bookmaker free bet and sign-up promotions.
Arbitrage (Arb)
Simultaneously backing all outcomes of an event across different bookmakers at odds that guarantee a profit regardless of the result.
For informational and educational purposes only. Disclaimer
