odds maker

/ˈɑdzˌmeɪkər/
noun
  1. A person whose job is to calculate and set the odds (probabilities) for betting on sports, races, or other events.
    • Before the big game, the odds-maker studied team statistics to set fair odds.
    • Many bettors rely on the odds-maker's numbers to decide where to place their money.
    • The odds-maker predicted the underdog would win the championship.