We built 240 football accumulators at the four operators in our guide with acca-boost promotions — Marlin, Crestly, Bramble and Stadion — and priced each one fair, boosted and unboosted. The boost percentage rises with the number of legs. So does the margin, faster.
At three legs the average compounded margin across the four was 13%, and no operator boosts a three-fold. At five legs it was 22% and the boosts began, at 5% to 10%. At ten legs the margin was 48% and the boosts were 25% to 35%. At fourteen legs, where Marlin’s 50% applies, the underlying margin was over 80%: the boost leaves the bettor paying more than on an unboosted double.
None of the four operators is doing anything dishonest. The terms are clear, the boosts are applied automatically and the percentages are real. What the promotion does is make the most expensive product on the site look like the most generous one, and our promotions scoring — which rates real value after wagering, odds floors and expiry — now reflects the compounded margin behind each boost rather than the headline figure.
The accumulators guide sets out the arithmetic. The short version: two or three legs on sharp main lines, at the best price you can find for each, is the most an accumulator should be. A boost on anything larger is a discount on the wrong thing.
