Yes, betting on horses to lose is actually a thing. In horse racing betting circles, the term used is Lay Betting. It is considered easier compared to betting on the winner. However, lay betting works differently as you as the gambler set the odds for this bet. If the horse loses, the betting site pays in the staked amount multiplied by the odds value. However, if the horse wins, the bettor has to pay the bookie the amount lost. It is one of the simplest bets to make, but the risks involved are high as the gamer acts as a bookmaker.