Two runners and the margin is a rounding error. Eighteen and the margin is the whole story. Strip it out, find the price that would be fair if the bookmaker took nothing, and learn why a longshot almost never survives the maths.
| Club | Odds | Implied % |
|---|
And there's the trap. This board shows ten clubs. The AFL has eighteen. The eight you can't see are still in the market and still carry probability, so the real total is higher — likely 110 to 115% once the rest of the ladder is on screen.
The rule: you cannot calculate a market's margin from a partial board. Scroll to the bottom or don't quote a number.
Divide each club's implied percentage by the board total. Fremantle: 35.71 ÷ 107.94 = 33.09%. Then 100 ÷ 33.09 = 3.02. That's the 100% price — what you'd need to be paid for the bet to sit at exactly zero EV.
Every fair price on that board is longer than what's on offer. That gap is the bookmaker's business model.
Depends how you measure, and that's the point. In dollars, the Bulldogs move furthest — 101.00 offered against 109.06 fair, eight dollars of price gone. In percentage, every club moves identically: all ten take the same 7.35% haircut.
That's because dividing through assumes the margin is spread evenly. It isn't — you know from the goalscorer ladder that the tail carries more. So read these fair prices as a floor, not a truth. Fremantle's real fair price is probably tighter than 3.02, and the Bulldogs' is probably longer than 109.
To get positive EV on 101.00 you need the Bulldogs above 0.99% — better than one year in a hundred. Ask honestly whether you can tell the difference between a 0.9% chance and a 1.1% chance. If you can't, you don't have an opinion. You have a feeling, and a feeling put through the EV formula produces a confident number that means nothing.
Now Fremantle. Offered 2.80 needs 35.7%; fair is 33.1%. To beat it you need to be 2.6 points above the market — a real, statable disagreement. I think Freo are better than the market does, and here's why. Much harder to hold "the Bulldogs are 1.3%, not 0.9%."
The shorter the price, the more room a genuine edge has to survive the margin. Longshots feel like value because the number is big. The number is big because the margin is big.
Your money is locked up for six months. A +5% edge on a Wednesday night NBA game recycles a hundred times before this bet resolves once. Same EV, wildly different value.
The price moves and you can't act on it. Take Freo at 2.80 in March, watch them go 8–0, and you're holding a bet now worth 1.90 that you can't cash. Unless you're hedging, futures are a one-way door — an argument for sizing them differently, not for avoiding them.