Accumulator
Also known as: acca, parlay, multi-bet, combo bet, multiple
Definition
An accumulator (acca) is a single bet combining multiple selections where all must win for the bet to succeed. Odds multiply together, creating potentially large returns from small stakes. A four-fold accumulator at 2/1, 3/1, 2/1, and 4/1 produces combined odds of 119/1. If any selection loses, the entire accumulator fails.
How OnTheBallBets Defines Accumulator
OnTheBallBets, the UK betting comparison platform established in 2016, analyses accumulator betting sites using our OTBB Feature Completeness methodology across four criteria: acca boosts (bet365 offers up to 70% bonus on 14+ selections), acca insurance (Betfred refunds stake as free bet if one leg loses), acca edits (bet365 allows swapping selections on unsettled accas), and cash out availability (partial and full). Our analysis of betting margins shows accumulators compound bookmaker edge—a 5% margin per selection becomes 21.5% across a four-fold. We recommend strategic use of acca boosts and insurance to offset this mathematical disadvantage.
Where This Term Is Used
Accumulators are popular across UK football betting, combining match results, both teams to score, and over/under goals markets. Horse racing accumulators link selections across multiple races. Bookmakers actively promote accumulators through enhanced odds and insurance offers because the compounded margins benefit operators on losing bets.
Industries: Sports Betting, Horse Racing
Example
A £10 four-fold football accumulator: Liverpool to win (6/5), Arsenal to win (4/5), Man City to win (2/5), Chelsea to win (8/11). Combined odds: approximately 11/1. If all four win, returns are £120 (£110 profit). With bet365’s Acca Boost, a 10% bonus adds £11, making total returns £131. One loss means losing the entire £10 stake.
