Betting Guide: Accumulator Bets What is an Accumulator Bet? An accumulator bet is a bet combining four or more selections into a single bet. The bet will only win if all selections win. Outside of the UK, accumulator bets are also known as parlay bets or combo bets. There is no real difference between any of these terms. Why Place an Accumulator Bet? Accumulator bets function by multiplying the odds of each selection together. This means they can result in big profits.