Glossary fundamentals
Parlay
In short: A combined bet where multiple selections must all win for the bet to pay. The odds multiply across legs, producing larger potential payouts but compounded vig that heavily favors the book.
Also known as: accumulator, combo bet
Parlays are popular because the payouts look attractive, but the vig compounds with each leg. A two-leg parlay at standard -110 pricing has effectively 9.5% vig — roughly double a single bet. Ten-leg parlays are practically guaranteed profit for the book over time.