Betting & odds
Multiples
A multi combines two or more selections into a single bet where every leg must win for a return, with the odds multiplied together. Multis are popular because the quoted return is large, but each leg also multiplies the bookmaker's margin — a four-leg multi carries roughly four times the built-in edge against the punter. The margin compounding is why multis are among the most profitable products a bookmaker offers.
In use
Four legs at $2.00 each quote $16.00, but carry four margins rather than one.