Horse Racing Odds
For any given horse, you can see the best available price highlighted, and the difference between the best and worst price is often two or three points of odds — the difference between 7/1 and 5/1 on the same horse in the same race. It does not require you to do anything special — just take an early price on a race where BOG is offered. Unlike free bets, which come with qualifying conditions and wagering requirements, BOG applies to every qualifying bet you place. A few bookmakers restrict BOG to races shown on ITV or feature meetings, excluding the smaller afternoon cards where drifts are more common. That means BOG triggers on a meaningful proportion of bets, and the average uplift when it does trigger is typically between half a point and two full points of odds. Research on UK racing suggests that around 35 to 40 per cent of runners drift to a higher SP than their morning price.
On horses that drift — less money than expected, price lengthening — BOG gives you the benefit of the higher SP. On horses that are supported in the market — money coming in, price shortening — BOG adds nothing, because the SP is lower than the price you took. Best Odds Guaranteed is one of the most powerful tools available to horse racing punters, and it is routinely undervalued. 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.
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.
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.
In today’s day and age where automobiles have substituted the four legged animal, horses still retain importance. Dave Massey previews Saturday’s action at Aintree, selecting his best bets for the races at 1.15, 1.45, 2.25 and 3.00. Dave Chisnall spoke to kwiff on Friday afternoon just before he kicked off his Grand Slam of Darts qualifying campaign That small time investment — repeated across every bet you place — is the most reliable edge available to the average punter. 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.
The value of BOG depends on how much Starting Prices drift from the early prices. That decline puts pressure on bookmakers to attract and retain bettors. It is a one-way ratchet in the punter’s favour — a free option on upward price movement with no downside risk. Check the exchange price on your selection before placing with a bookmaker. When should you use the exchange, and when should you use a bookmaker?
The worst overrounds appear in ante-post markets, where the uncertainty justifies — in the bookmaker’s view — margins that can reach extraordinary levels. The overround also tells you something about the race itself. The overround is 5.9 per cent, meaning the bookmaker has built a theoretical edge of just under 6 per cent into the market.
There is a subtlety that experienced exchange users understand and newcomers often miss. Flutter Entertainment, which owns Betfair, reported global revenue of $14 billion in 2024 across 13.9 million average monthly users, but the exchange is only one part of that portfolio, and liquidity varies enormously by market. Hundreds of thousands of pounds are matched, and the spread between the back and lay prices is narrow. 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).
Over time, backing at exchange odds rather than bookmaker odds produces a measurably higher return on investment, assuming you can find liquidity on your chosen market. The exchange takes a commission betting sites not with gamstop on the net winnings of the winning side, typically between 2 and 5 per cent depending on the user’s activity level. 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.
