Acca Insurance, Priced Leg by Leg

The terms that decide the value

Many sportsbooks run acca insurance, and the wording differs from site to site, but the same handful of conditions turns up in the terms each time.

• Minimum number of legs. The slip must carry at least a set number of selections; five is the figure used in our example.
• Minimum price per leg. Each selection must be priced at or above a floor, for example 1.50. This stops a slip being padded with near-certainties that would make a one-leg miss far more likely.
• Minimum combined price, sometimes stated instead of, or as well as, the price per leg.
• Refund form. Cash, bonus balance that must be wagered, or a bonus bet where only the winnings are paid.
• Refund cap. The largest stake the promotion will return. Anything staked above it carries no cover.
• Exclusions. Cashing out, editing the slip or a leg being voided can each remove the cover. Some promotions also leave out in-play legs or bet builder selections.

The refund form and the cap move the value the most. The rest decide whether the slip qualifies at all.

How often exactly one leg loses

Take five selections at decimal prices of 1.70, 1.85, 2.00, 1.60 and 2.20. The combined price is 22.1408, so a stake of 10 returns 221.41 if all five win. To estimate the true chance of each leg, assume every market is a 105% book and strip the margin out: the fair probability is 1 divided by (price × 1.05).

The chance that one particular leg is the only loser is the chance it loses multiplied by the chance the other four all win. Add the five figures and you have the chance the cover is triggered.

Unrounded, the last column adds up to 17.05%. Set beside the other outcomes:

• All five win: 3.54%, about one slip in 28.
• Exactly one loses (refund): 17.05%, about one slip in six.
• Two or more lose: 79.41%, roughly four slips in five, with no refund.

The longest price, leg 5, is the most likely lone loser. The pattern holds generally: the leg most likely to let you down is the one the cover most often pays out on.

The shorter the legs, the more often a slip misses by one. With every leg at the same chance of winning, the share of five-folds that end one leg short looks like this:

At 80% a leg, the refund would be triggered on two slips in five. That is exactly why the terms set a minimum price per leg: it keeps the selections long enough that the near miss stays the minority result.

What the refund is worth after wagering

A refund of 10 is only worth 10 if it arrives as cash. Here are the three common forms, with the same 105% book assumed on whatever the refund is bet on. At that margin, every unit staked returns about 0.9524 on average, so the bettor gives up about 4.76p per pound.

1. Cash. Worth the full 10.00.
2. Bonus balance with 3x wagering. The 10 must be bet through 30 in total before it becomes withdrawable. Expected loss on that turnover: 30 × 0.0476 = 1.43. Value about 8.57.
3. Bonus bet, stake not returned, at a price of 2.00. It wins 47.62% of the time and pays only the profit of 10. Value 0.4762 × 10 = 4.76.

The gap between the first and last line is more than half the refund. The guide to wagering requirements shows how the multiple and the minimum odds move the second figure.

The expected value of an insured five-fold

Without any cover, the slip returns 221.41 with a chance of 3.54%, which is 7.84 back for every 10 staked. The expected loss is 2.16, the margin of five legs compounded. Acca insurance adds the chance of a one-leg miss, 17.05%, multiplied by the value of the refund.

Even paid in cash, the cover does not turn this slip into a winning proposition. It wins back about 79% of the margin when the refund is cash, about 68% as wagered bonus balance and about 38% as a bonus bet. That is real value, and it is worth having on a slip you were going to place anyway. It is not a reason to place one.

The cap changes the sums quickly. Stake 50 on the same slip with cover limited to 25. The expected loss without cover is 10.82; a cash refund of 25 on 17.05% of slips adds back 4.26, leaving −6.56, or −1.31 per 10 staked. Every unit above the cap carries the whole five-leg margin and no cover at all.

How margin builds up across the legs

The cost the cover has to beat comes from the prices, not from the promotion. On a five-fold, the margin on each leg is multiplied into the next, so a small difference per leg becomes a large one on the slip.

Moving every leg from a 105% book to a 103% book saves 0.79 per 10 staked, almost exactly what the cover is worth when the refund is a bonus bet. Better prices across the slip can match the promotion on their own. The acca calculator multiplies the prices and settles void legs, the odds and margin converter measures the book on any market, and the lowest-margin sportsbooks are compared on a separate page.

Acca insurance and document checks

A refund paid as a bonus brings the account under the bonus terms, and that matters at a site you joined without sending documents. Bonus terms usually give the operator the right to review an account before any bonus winnings are paid, and that review can include a request for ID or proof of address. One offer per person or per household is the usual rule, and documents are how it is enforced.

The same applies to the slip that wins. A five-fold at a combined 22.14 turns a modest stake into a sum that can cross a withdrawal threshold, and a large return is one of the common reasons for a check. Read the threshold before the slip goes on. The no-KYC casinos page sets out what tends to trigger a request, and the crypto betting sites we rate list their own terms.

Common mistakes

• Adding a leg to qualify. A sixth selection at a 105% book cuts the slip's expected return by another 4.76%, and it makes the one-leg miss rarer: with every leg at 50%, the chance of exactly one loser falls from 15.63% on five legs to 9.38% on six.
• Cashing out early. Most terms cancel the cover once any part of the slip is cashed out, so a near miss after a partial cash-out earns nothing.
• Staking above the cap. The extra stake is uninsured and pays the full margin.
• Treating a bonus bet as cash. At even money it is worth under half its face value.
• Forgetting void legs. A postponed match can drop the slip below the minimum number of legs and take the cover with it, even though the bet still stands.

When acca insurance is worth taking

Our view: take the cover when it comes with a slip you would have built anyway, at the stake you would have used, with legs priced at or above the floor for your own reasons. Do not lengthen a slip, shorten your prices or raise your stake to fit the promotion. For a price promotion that works on singles, the odds boost guide does the same sums, and the welcome bonus guide covers offers tied to a first deposit. Every bonus type we cover is listed in the bonuses section. If accumulators have become the way you chase a loss, the responsible gambling page lists tools and help.

Our ranking of betting sites that don't ask for ID shows which operators name a sum for ID checks and which leave it open.

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