Betting
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 non gamstop bookmakers qualify. There are practical considerations that limit BOG value. Using the exchange as a benchmark — even if you ultimately bet with a bookmaker — is one of the most effective habits a punter can develop. If the exchange offers 7.0 and the bookmaker offers 5/1, the bookmaker is taking a significantly larger margin on that runner, and you should either back on the exchange or find a bookmaker whose price is closer to the exchange level. If the exchange offers 6.0 and the bookmaker offers 5/1, the bookmaker is competitive after commission.
If prices consistently drift after you bet, something in your analysis may need adjustment. Value exists in the gap between your probability assessment and the bookmaker’s implied probability. A horse at 2/1 (33% implied probability) that you assess as a 25% chance is not—even though the shorter price might feel safer. A horse at 4/1 (20% implied probability) that you assess as a 25% chance is a value bet.
The difference (28% vs 22.2%) represents potential value—the bookmaker is underestimating this horse’s chances according to your analysis. At decimal odds of 6.00, a £10 bet returns £60 total—your £10 stake plus £50 profit. The first number represents potential profit; the second represents the stake required to generate that profit. At 7/2, the same £1 stake returns £3.50 profit plus stake, totalling £4.50.
Then let the market move as it will—your downside is protected, and any drift converts into bonus profit. Strategic use of BOG requires understanding when to bet and when to wait. This promotion exists because bookmakers are competing for early-morning turnover. A six-runner race where implied probabilities sum to 112% has a 12% overround—meaning the bookmaker’s theoretical margin is 12% before any punter places a bet. But without calculating implied probability, you cannot begin to answer that question systematically.
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. 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. If you bet at a bookmaker with a consistently higher overround, you need a higher strike rate just to break even. Checking the overround before you bet is not something most punters do, but it takes less than a minute with a calculator or an odds comparison site.
That habit—questioning, comparing, calculating—is the foundation of profitable betting. Before your next racing bet, check three bookmakers for the price. The only requirement is the discipline to use them consistently, rather than defaulting to convenience. Place terms and extra places offers are announced in advance. Festival betting offers concentrated opportunities where liquidity and promotional competition peak.
That difference — roughly 10 per cent on the individual price — is the cost of the bookmaker margin. The exchange takes a commission on the net winnings of the winning side, typically between 2 and 5 per cent depending on the user’s activity level. Instead of setting odds and accepting bets against them, the exchange matches punters on opposite sides of a bet. The betting exchange — Betfair being the dominant platform — operates on a fundamentally different model to a traditional bookmaker.
Understanding the specific dynamics of each major meeting is essential for capturing available edge. Pricing generally competitive without being consistently best. Part of the Entain group alongside Ladbrokes with shared liquidity benefiting pricing stability.