Outright markets, the tournament winner, the top scorer, the season-long futures, are where margin removal gets hardest. The prices are long and uneven, the overrounds are the biggest on the board, and the modeling assumption you chose barely matters on a coin-flip starts to matter a lot. Here is what changes when you run the same math on a futures market.
The margin is bigger and less evenly spread
A soccer match winner market might carry a few percent of overround; an outright with a dozen runners can carry several times that. The no-vig calculator accepts up to twelve outcomes, which covers most outright boards, checked 2026-10-05. What the calculator cannot tell you is how the margin is distributed across the runners, because that is the modeling choice, not a measurement.
On uneven prices the choice bites. Proportional removal takes the same relative share from every runner; the power method takes more from the longshots. On an outright board, where one favorite might sit at 2.00 and half the field at 20.00 or longer, the two methods produce visibly different fair prices, and the gap grows with the overround.
A worked look at the strain
Take a four-runner market priced 1.80, 3.00, 5.00 and 8.00. The implied probabilities sum to 0.5556, 0.3333, 0.20 and 0.125, a total of about 1.2139, so the overround is roughly 21%. Proportional removal divides everything by 1.2139 and returns fair prices of 2.19, 3.64, 6.07 and 9.71. The favorite's fair price moved by the same 21% as the outsider's, because proportional treats all runners alike.
The power method tells a different story: it fits an exponent that pushes more of that 21% onto the longshots, so the favorite's fair price stays closer to 1.80. Neither is the truth. The methods diverge exactly here, and the outright is where the divergence stops being academic.
The practical rules for long markets
First, completeness is harder and more important. An outright board with a missing runner is not a smaller market; it is a broken one, and every fair price from it is wrong by the missing runner's share. Use the full board or nothing.
Second, state your method next to every fair price you publish or store. On a futures market the method is a bigger source of difference than on any match, and a reader comparing your fair prices against someone else's needs to know which model produced them.
Third, distrust precision. A fair price of 9.71 computed from an overround near 21% is a model's estimate, not a measurement; the calculator itself notes that it does not establish true probabilities, and that note is loudest on long markets.
Futures are where the margin lives largest. Remove it with the full board, a stated method, and a humble number of decimal places.