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.
A lay bet is the opposite of a back bet. When you lay a selection, you are betting that it will not win — you are taking the bookmaker role. On a betting exchange, you offer odds to a backer. If the selection loses (or draws), you collect their stake. If it wins, you pay the liability: stake × (decimal odds − 1).
Lay betting is only available on betting exchanges such as Betfair, Smarkets, and Matchbook. Traditional bookmakers only accept back bets — they are always on the lay side. Exchanges connect backers and layers directly, taking a commission (typically 2–5%) from net winnings.
The fundamental lay betting strategy mirrors value betting in reverse: identify selections priced shorter than their true probability (underlays) and lay them. If a team is priced at 1.4 but your model gives them only a 55% chance of winning (fair odds ~1.82), laying them at 1.4 creates positive expected value.
Lay betting is also central to trading strategies — particularly lay the draw, where you back a team pre-match and lay the draw in-play after they score, locking in a guaranteed profit across all outcomes (greening up). Exchange commission must be factored into all lay strategy calculations.
Value Betting
Betting at odds that are higher than the true probability of the outcome — finding bets where the bookmaker has underestimated the chances of an event.
Implied Probability
The probability of an outcome embedded in bookmaker odds — calculated by dividing 1 by the decimal odds.
Expected Value (EV)
The average outcome of a bet over a large number of repetitions — positive EV means the bet profits long-term; negative EV means it loses.
CLV (Closing Line Value)
The difference between the odds you backed and the odds at match kick-off — the best long-term predictor of whether your betting strategy has a genuine edge.
Overround (Vig / Juice)
The bookmaker's built-in profit margin — the amount by which the implied probabilities of all outcomes in a market sum to more than 100%.
For informational and educational purposes only. Disclaimer
