What is a “key box” in horse racing betting?
To understand how a key box works you should first know that a straight box is a single-race wager that requires you to select the top finishers in a certain race – bets like exactas, trifectas, superfectas, etc.
For example, if you bet a straight $/£2 exacta on the 4 and 2 horses, they must finish in that order for you to win. Boxing the bet doubles the cost of the ticket to $/£4, but ensures you will collect as long as they are top two finishers in the race, no matter what order they finish in. You can box as many horses as you wish, but each time you add a horse the price of the ticket escalates.
A four-horse box with a base $/£2 bet, for example, costs $/£24. A key box is built on the same concept, but it focuses your financial firepower on one or a few horses – the “key” horse(s) – and can be used in both single-race and multiple-race wagers (Daily Doubles, Pick 3s, Pick 6s, etc.).
Here’s an example, if you’re playing a Pick 3 at Saratoga and you really like a horse in the first race in the sequence, you can key or single that horse on a ticket and then spread out in the subsequent to legs. In that case, your base bet $/£1 bet might look like this: 1 horse in the first leg; 3 horses in the second leg; and 7 horses in the third, for a total cost of $/£21 (1x3x7=$/£21).
In such a scenario, if your key horse rewards your faith, you have a much improved chance of collecting the Pick 3. If not, you are dead after the first race is run, no matter what happens to your other choices.