Sportsbooks welcome parlays because of their significant house edge. For instance, if you pick five teams on a parlay to cover the spread and those picks go 4-1, the bet is a loser. Sports betting parlays involve the selection of two or more propositions on a single wager, with each separate portion of a parlay called a 'leg.' All legs of a parlay must win for the bet to become a winner. It's a widespread belief that parlays are mostly done by novice sports bettors, but experienced handicappers are known to play them as well. Parlays are popular wagers among bettors because of the appeal of potentially winning a hefty sum with a minimal investment.