Many Thoroughbred stallions are being bred to increasing numbers of mares. This practice raises the question of how progeny value is affected by an increased supply of foals by the same sire, which ultimately influences the sire’s value. This paper addresses that question. Three of the four models presented in our study find that the average price of a sire’s yearlings is increasing in sire representation. In addition, greater sire representation decreases the likelihood that a yearling is removed from the sale, but may increase the likelihood that it does not meet its reserve price.