Optional Claiming Race Designation, Daily Racing Form, 1954-05-12

Optional Claiming Race Designation Optional claiming races are indicated by a superior "O" immediately proceeding or following the claiming price. A superior letter "O" preceeding the claiming price indicates that the horse was not entered to be claimed. A superior letter "O" following the claiming price indicates that the horse was entered to be claimed. Note: The latter is being used only for optional claiming races run on or after April 10, 1954;