The most common kind of TwinSpires bonus is the “Winsurance”-style bonus in which players opt into the bonus then bet a specified amount and receive a percentage of the losing ticket costs as bonus funds for future races. The second most common kind of bonus is the carryover pool—essentially a lottery drawn from players who bet on the various races in a series. If no one wins during a given week, the funds grow, and another drawing occurs during the following week.