Along with yachts, private jets, mansions and Ferraris, we can now add another elite asset class that’s ailing: thoroughbred horses.

The annual Keeneland September yearling sale finished up in Kentucky over the weekend. It is like the Super Bowl of horse buying, and yearling sales (yearlings are thoroughbred racehorses that are one year old dating from January 1 of the year in which it was foaled).