The bookmaker functions as a market maker for sports wagers, most of which have a binary outcome: a team either wins or loses. The bookmaker accepts both wagers, and maintains a spread (the vigorish) which will ensure a profit regardless of the outcome of the wager. The Federal Wire Act of 1961 was an attempt by the US government to prevent illegal bookmaking. However, this Act does not apply to other types of online gambling. The Supreme Court has not ruled on the meaning of the Federal Wire Act as it pertains to online gambling. (資料來源)
Odds for different outcomes in single bet are presented either in European format (decimal odds), UK format (fractional odds), or American format (money line odds). European format (decimal odds) are used in continental Europe, Canada, and Australia. They are the ratio of the full payout to the stake, in a decimal format. Decimal odds of 2.00 are an even bet.
UK format (fractional odds) are used by British bookmakers. They are the ratio of the amount won to the stake – the solidus “/” is pronounced “to” for example 7/1 “seven to one”. Fractional odds of 1/1 are an even bet. US format odds are the amount won on a 100 stake when positive, and the stake needed to win 100 when negative. US odds of 100 are an even bet. (資料來源)
