Prediction markets vs sportsbooks

At a traditional sportsbook you bet against the house. On a prediction market exchange you trade a contract against other people. That one structural difference changes almost everything downstream: who sets the price, what the price means, and where the cost hides. This guide compares the two venues as structures, not as products, so you can read either one clearly.

Who sets the price, and what it means

A sportsbook posts a price and takes the other side of your bet. To cover its risk and earn a margin, it builds a cushion into the odds called the vig. Add up the implied probabilities of every outcome at a sportsbook and they total more than 100 percent. That overage is the house margin, and it is why the posted odds are not a clean probability.

An exchange works differently. Buyers and sellers meet at a price, and on a fixed-payout contract that price is a probability. A contract paying one dollar if an event happens might trade at 63 cents. Reading that as about a 63 percent chance is the same move you make when you turn odds into implied probability, except here the market hands you the number directly instead of hiding it inside a payout.

In this made-up example both venues describe the same event. The sportsbook price of -170 has a margin folded in, so its raw implied chance reads a little high. The exchange price of 0.63 is the crowd's balance point, closer to a plain probability once you account for fees.

Where the cost lives

At a sportsbook the cost is the vig, a known cushion inside a single price you can read before you bet. On an exchange the cost is a spread plus fees, and it varies with how much trading is happening. A busy contract may have a spread of a cent or two; a quiet one may cost far more to enter and exit. Neither structure is free. They just present the cost in different places, and a literate reader learns to spot both.

What each does better

Sportsbooks are simple and instant. A price is posted, you take it or leave it, and thousands of markets are available at once, including niche ones no exchange would have enough traders to support. That breadth and immediacy is a real strength.

Exchanges give you a cleaner probability and, often, the ability to exit a position before the event resolves rather than being locked in until the end. The tradeoff is that an exchange only works when enough people are trading a given contract. Thin markets mean wide spreads and prices that can lurch on a single order.