Betting
That difference — roughly 10 per cent on the individual price — is the cost of the bookmaker margin. One person backs a horse to win; another lays it (bets against it winning). The betting exchange — Betfair being the dominant platform — operates on a fundamentally different model to a traditional bookmaker. Among fixed-odds bookmakers, bet365, Paddy Power, and William Hill tend to be competitive on feature races, while some smaller operators run wider books, particularly on less prominent meetings. By the time the race starts, competition among operators has usually tightened the market. Bookmakers open with a cautious book and adjust as money comes in.
The overround is 5.9 per cent, meaning the bookmaker has built a theoretical edge of just under 6 per cent into the market. It is the bookmaker’s theoretical profit margin before a single bet is settled. In practice, they always sum to more — typically between 110 and 130 per cent for horse racing — and that excess is the overround. In a perfectly fair market with no margin, the implied probabilities of all runners in a race would sum to exactly 100 per cent. Understanding those differences is where value lives.
The bookmaker margin is built into every price, but how wide that margin is varies enormously between operators, between race types, and between the fixed-odds market and the betting exchange. Horse Racing Odds Comparison — More on this topic at horse racing bookmakers. Yet the majority of bettors place their bets with whichever app they last used, at whatever price happens to be on screen, without checking whether a better number is available elsewhere.
The overround on the Grand National ante-post market can reach as high as 180 per cent — a level that would be considered predatory in any raceday market. It varies by operator, by race type, and by the time of day. If Bookmaker A is running a 115 per cent book on a race and Bookmaker B is running a 125 per cent book, Bookmaker A is systematically offering better value across the entire field.
Around major meetings — Cheltenham, the Grand National, Royal Ascot — bookmakers offer boosted prices on selected runners. If the non gamstop esports betting exchange offers 6.0 and the bookmaker offers 5/1, the bookmaker is competitive after commission. Instead of setting odds and accepting bets against them, the exchange matches punters on opposite sides of a bet. At the upper end, you find big-field handicaps with 20 or more runners, where each horse price can be inflated by a few ticks without any individual punter noticing the difference. The individual difference may be small — perhaps 5/1 versus 11/2 — but across hundreds of bets over a year, that cumulative margin is the difference between a profitable punter and a losing one. The take varies from state to state and the money is used to pay taxes, purse money for the horsemen, expenses at the track, and the track’s profit.
If you are betting early in the day and BOG is on offer, take the best available bookmaker price. If the exchange back price is 8.0 and the best bookmaker is offering 6/1, the bookmaker is taking a significantly wider margin on that horse. Here is the workflow that experienced punters follow, stripped of anything unnecessary. And some operators apply BOG only to bets placed after a certain time in the morning, which means very early ante-post-style wagers do not qualify. Most bookmakers cap BOG payouts — some at a maximum enhanced payout of 500 pounds, others at a maximum uplift of a certain number of odds points.
The first show of prices in the morning — often called the early prices — tends to carry a wider margin than the Starting Price. On the raceday market itself, there are consistent patterns. Ante-post markets on the Cheltenham Gold Cup or Champion Hurdle typically run between 140 and 160 per cent, which is lower than the National but still significantly wider than raceday. The aggregate effect across 20 runners adds up to a much wider margin than in a six-runner race. Across UK and Irish horse racing, typical bookmaker overrounds range from about 110 to 130 per cent.
Ross Burdon provides his latest stable update, with Gifts Differing set to run at Chelmsford on Thursday, while Dust Cover Manchester United host Aston Villa in Sunday’s featured Premier League clash, with both sides looking to build momentum. Hector Crouch heads to Southwell for three final rides on Saturday before jetting off to