Aside from simple wagers--betting a friend that one's favorite baseball team will win its division, for instance, or buying a football "square" for the Super Bowl--sports betting is commonly done through a bookmaker. Legal sports bookmakers exist throughout the world (perhaps most notably in Las Vegas). In areas where sports betting is illegal, bettors usually make their sports wagers with illicit bookmakers (known colloquially as "bookies") and on the Internet, where thousands of online bookmakers accept wagers on sporting events around the world. (In the United States, the legality of Internet wagering is ambiguous, due to the fact that online bookmakers generally operate outside of the U.S. Many online bookmakers do not accept wagers from the U.S. due to these unresolved legal questions.) The bookmaker earns a commission or "vigorish" by regarding the money at risk as less than the size of the bet placed. A common line is a $110 bet on a fair coin which pays $210 to win and $0 to lose. On this line, it costs $220 to bet both sides of the same coin simultaneously, but the combined bet always pays $210.

Bookmakers generally offer two types of wagers on the winner of a sporting event: a straight-up or money line bet, or a point spread wager. Moneylines and straight-up prices are used to set odds on sports such as soccer, baseball and hockey (the scoring nature of which renders point spreads impractical) as well as individual vs. individual matches, like boxing. For these sports, bookmakers in Europe and Asia generally use straight-up odds, which are quoted based on a payout for a single bet unit; for example, a 2-1 favorite would be listed at a price of 1.50, whereas an underdog returning twice the amount wagered would be listed at a price of 3.00.

American bookmakers generally use moneylines, which are quoted in terms of the amount required to win $100 on a favorite, or the amount paid for a $100 bet on an underdog. The amount "won" in a bet is the net amount over and above the initial bet. If a person wins $200 on a bet of $100, the bookmaker actually pays the winner $300 (i.e. $200 plus the initial bet of $100).

For example, a baseball game between the St. Louis Cardinals and Chicago Cubs might have a moneyline on St. Louis (the favorite) at -200 and Chicago (the underdog) at +180. A bettor looking to take St. Louis must risk $200 for every $100 he wishes to win over and above the initial $200 bet. A person wagering on Chicago will win $180 for every $100 he bets.

The +180 moneyline on Chicago includes a 20 cent "dime line". Bookmakers generally use a "dime line" with moneylines to calculate the vigorish they receive on losing wagers. Without the 20 cent dimeline in the example above, the Chicago moneyline would be +200.

For favorites of -120 to -150, the difference between the favorite and underdog is 10 cents; i.e., the underdog to a -120 favorite is priced at +110. The discrepancy between prices rises for favorites of -160 or higher.

Unlike point spread bets, a moneyline wager requires only that the team wagered upon win the match. In sports such as baseball, where certain teams can be heavy favorites against weaker opponents (sometimes as much as -350 or higher), the moneyline system requires that a hefty sum be risked on the favorite, while enticing underdog players with a higher payout.

In sports such as basketball and American football, rather than varying the money odds (which can be substantial in lopsided matches), the point spread is used. A point spread wager typically requires a bettor to risk $110 to win $100, the extra $10 being the bookmaker's vigorish if the wager loses. However, bettors backing the favorite collect only if their team wins by more than a specific victory margin, which is set at the time of the wager. Similarly, underdog bettors can collect even when their team loses, as long as they cover the point spread by losing by fewer points than were quoted by the bookmaker. For example, suppose that a college football game between Oklahoma and Kansas had Oklahoma as a 27 point favorite (quoted as Oklahoma -27, or Kansas +27):

• If Oklahoma defeats Kansas by more than 27 points, bettors on Oklahoma would receive $100 on a $110 bet. Kansas bettors lose the $110 they wagered.
• If Kansas defeats Oklahoma, bettors on Kansas would receive $100 on a $110 bet. Oklahoma bettors lose the $110 they wagered.
• If Kansas loses by less than 27 points, they have covered the spread. Bettors on both sides are then treated exactly as if Kansas had won the game.
• If Oklahoma wins by exactly 27 points, the wager is called a "push", and neither side wins. Standard practice by U.S. bookmakers is to return the stakes of all bettors on the game in full. To prevent pushes and ensure that they receive their commission on losing wagers, bookmakers often set point spreads that include a half-point.

Another common wager available for sporting events involves predicting the combined total score between the competing teams in a game. Such wagers are known as "totals" or "over/unders." For example, the Oklahoma/Kansas football game described above might have a total of 55 points. A bettor could wager that both teams will combine for over 55 points, and play the "over." Or, she could predict that the score will fall under this amount, and play the "under." As with point spreads, bookmakers frequently set the totals at a number involving a half-point (i.e., 55.5), to reduce the occurrence of pushes.

Many bookmakers offer several alternative bets, including the following:

• Proposition bets. These are wagers made on a very specific outcome of a match. Examples include guessing the number of goals each team scores in a soccer match, betting whether a wide receiver in a football game will net more or less than a set amount of total yardage, or wagering that a baseball player on one team will accumulate more hits than another player on the opposing team.
• Parlays. A parlay involves multiple bets (usually up to 12) and rewards successful bettors with a large payout. For example, a bettor could include four different wagers in a four-team parlay, whereby he is wagering that all four bets will win. If any of the four bets fails to cover, the bettor loses the parlay, but if all four bets win, the bettor receives a substantially higher payout (usually 10-1 in the case of a four-teamer) than if he made the four wagers separately.
• Run line, puck line or goal line bets. These are wagers offered as alternatives to straight-up/moneyline prices in baseball, hockey or soccer, respectively. These bets feature a fixed point spread that offers a higher payout for the favorite and a lower one for the underdog. For example, the above-described Cardinals/Cubs baseball game might offer a run line of St. Louis -1.5 (+100) and Chicago +1.5 (-120). A bettor taking St. Louis on the run line can avoid risking $200 to win $100 on the moneyline, but will collect only if the Cardinals win by 2 runs or more. Similarly, a run line wager on the Cubs will pay if Chicago loses by no more than a run, but it requires the bettor to risk $120 to win $100.
• Future wagers. This bet predicts a future accomplishment by a team or player. One example is a bet that a certain NFL team will win the Super Bowl for the upcoming season. Odds for such a bet generally are expressed in a ratio of units paid to unit wagered. The team wagered upon might be 50-1 to win the Super Bowl, which means that the bet will pay 50 times the amount wagered if the team does so.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.