Most pari-mutuel horse races in the United States are claiming races.In such races, a track official stipulates a claim price, and any authorized person may buy any horse that runs in that race at that price. This device discourages owners from running overqualified horses, which tends to ensure competitive fields. Say, for example, an official set a price of $50,000 for a race. An owner who ran a $60,000 horse in that race would stand a fair chance of picking up a good part of the purse, but he or she would also run a high risk of losing the horse to a claim for only five-sixths of its value. Meanwhile, an owner who ran a $40,000 horse in that same race would probably avoid a claim, but would also stand relatively little chance of picking up much of the purse, thereby wasting one of the horse’s starts. Claiming races thus cause fields to converge in quality, which tends to ensure competitive races. In fact, claiming races have this effect even if people are unaware of how they work, simply because people will see competitive races. If people believe races are competitive, they will bet more, which will generate more revenue for the track. Moreover, to the extent people do understand how claiming races work, they will be even more inclined to see them as competitive, because they will understand how the potential for claims monitors entries.
Salamanca, Paul E., "The Constitutionality of Claiming Jail" (2017). Law Faculty Scholarly Articles. 635.