[gruez]

>However if the action doesn't balance out, the book has considerable exposure if the team with more bets on it wins.

isn't that only an issue if the counterparty to each bet is the sportsbook? why can't a sportsbook operate like an exchange, with a bid/ask orderbook and take a % off each trade?

[TylerE]

Well, I mean, you could, but the point of a book is that they take action. It's like a market maker.

[tpm]

> why can't a sportsbook operate like an exchange

It can and some do. But it's nearly impossible to do combined bets (multiples, accumulator etc) in an exchange, and they are very popular. Also as already mentioned it's leaving money on the table.

[kasey_junk]

There are book exchanges.

Historically that was leaving money on the table though as squares outnumber sharps.

[repsilat]

It's not either-or, really. If you run an exchange you can bet on it (maybe depending on jurisdiction.) Then you get the commission or the winnings. IIRC matchbook.com do that though I may have been misinformed.

[adw]

You just described Betfair and Smarkets.