A lucky 15 bet is a special class of full cover bets in which all possible combinations will provide a win.
A Lucky 15 is a total of 15 individual bets which are made up from a combination of singles, doubles, trebles, and a four times accumulator.
If any of the selections win, then a return is guaranteed. This is because bookmakers offering Yankees will increase the odds on one of the singles winning in order to guarantee this return, which is generally at double the original odds. Often bookmakers will offer additional bonuses to increase the attractiveness of a Lucky 15.
The possible outcomes are not difficult to calculate but if you want to do it on the fly and you have a smart phone, then it might be useful to download an app to make the task somewhat simpler.
Here is an example of how a lucky 15 might work at the Cheltenham Festival. You decide to restrict yourself to horses at reasonable odds that look as though they have a reasonable chance of doing well.
Your choices are Long Run in the Arkle Trophy at 8/1; Maljimar in the Cross Country Handicap Chase at 9/1; Tidal Bay in the World Hurdle at 7/1; and Carlito Brigante in the Triumph Hurdle at 8/1. Paddy Power is offering double odds on a single win plus a bonus of 10%. You have decided to place a £1.00 Lucky 15.
Your total stake is £15.00 and if every one of your selections is a winner, then your total winnings are £9,989.00.
If your highest odds bet loses, you win £899.00; If your two highest odds bets lose you win £89.00; If your only winner is Tidal Bay at 7/1, you win £16.50.
It is apparent that you can win large sums of money on Lucky 15s. Recently a punter on Stan James placed a 50p Lucky 15 bet and won nearly £32,000.