sports betting

Odds for different outcomes in a single bet are presented either in European format (decimal odds), UK format (fractional odds), or American format (moneyline odds). European format (decimal odds) are favoured 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 favoured by British bookmakers. They are the ratio of the amount won to the stake. Fractional odds of 1/1 are an even bet. Moneyline odds are favoured in the United States. They are the amount won on a 100 stake when positive and the stake needed to win 100 when negative. Moneyline odds of 100 are an even bet.
Sports betting is the general activity of predicting sports results by making a wager on the outcome of a sporting event. Perhaps more so than other forms of gambling, the legality and general acceptance of sports betting varies from nation to nation. In the United States, the Professional and Amateur Sports Protection Act of 1994 makes illegal to operate a "betting, gambling or wagering scheme", except for in the states of Delaware, Nevada, and Oregon. Nevada, however, is the only state currently allowing sports gambling, while in many European nations bookmaking (the profession of accepting sports wagers) is highly regulated but not criminalized. Proponents of legalized sports betting generally regard it as a hobby for sports fans that increases their interest in particular sporting events, thus benefiting the leagues, teams and players they bet on through higher attendances and television audiences. Opponents fear that, over and above the general ramifications of gambling, it threatens the integrity of amateur and professional sport, the history of which includes numerous attempts by sports gamblers to fix matches, although proponents counter that legitimate bookmakers will invariably fight corruption just as fiercely as governing bodies and law enforcement do. Most sports bettors are overall losers as the bookmakers odds are fairly efficient. However, there are professional sports bettors that make a good income betting sports.
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. Some 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. The $10 loss constitutes the vig. There are opposing positions on whether the winner or loser can be construed as paying the vig, but this debate is not especially meaningful. If you view $110 to win $210 on a fair coin as $100 at risk, then it will appear as if the loser pays the vig; if you view the same line as $110 at risk, then it will appear as if the winner pays the vig. It happens that standard practice among bookies is to adjust odds so the amount at risk remains constant from the winning side of the proposition, hence the common perception that the loser pays the vig. Vigs expressed as percentages suffer from the same perceptual bias. On the line as given in this example, for a fair coin, the bookie has an expectation of making $5 for each $110 bet placed, which is often divided out and expressed as 4.5% Odds on teams or adversaries are quoted in terms of the favorite (the team that is expected to win, thus requiring a riskier wager) and the underdog.
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 association football, 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 Milwaukee Brewers and Chicago Cubs might have a moneyline on Milwaukee (the favorite) at -200 and Chicago (the underdog) at +180. A bettor looking to take Milwaukee 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 or American football, betting on the point spread is more popular, although money line odds are usually offered as well. 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. This is called "covering the spread". Similarly, underdog bettors can collect even when their team loses, as long as they win against the point spread by losing by fewer points than were quoted by the bookmaker. For example, suppose that a college football game between Kansas State and Kansas had Kansas as a 27 point favorite (quoted as Kansas -27, or Kansas State +27):
If Kansas defeats Kansas State by more than 27 points, they have covered the spread and bettors on Kansas would receive $100 on a $110 bet. Kansas State bettors lose the $110 they wagered. If Kansas State defeats Kansas, bettors on Kansas would receive $100 on a $110 bet. Kansas bettors lose the $110 they wagered. If Kansas State loses by less than 27 points, they have won against the spread. Bettors on both sides are then treated exactly as if Kansas State had won the game. If Kansas 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 Kansas State/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, he 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.
Most people believe that bookmakers adjust their prices so that they get the same amount of money on both sides of a game. Theoretically, the bookmaker's only financial interest in the bets it accepts is the vigorish it takes from losing wagers, and it simply wants to ensure that the amount of wagers on each side is equal. However, some bookmakers are willing to take more risk and attempt to maximize their bottom line. While having an exactly equal amount of money wagered on each contestant would guarantee themselves a profit and eliminate their risk, that won't necessarily maximize their bottom line. They can make more money when they accept bets at odds which are "inflated" from those which are likely to occur. So for example, if the majority of their customers are going to bet on a team regardless of the price, they will set the price as high as possible. This is called "shading" the line. Generally, the public prefers to back the favorite, and unsophisticated bettors often show up during large events such as the Final Four and the Super Bowl. Some bookmakers actually offer different prices to different customers, using past bets as an indicator of who the customer will bet on as a way of additionally increasing their potential profit. This practice is known in the industry as offering "dual lines".
Traditionally, home advantage in American football betting leads to three points being added to the spread; for instance, if two identical teams, Alpha and Beta, played at Beta's home field, then the spread would be Beta -3 (or, conversely, Alpha +3).
With a match offering a point spread, however, bookmakers must be careful of moving the line too much. Assume, for example, that a large number of Oklahoma betters caused the line to be moved from 27 points all the way to 29 points. If Oklahoma won the game by 28 points, the bookmaker would have to pay both those who wagered that Oklahoma would win by 27 and those who took Kansas on the 29 point spread. Bookmakers refer to such an event as "being middled." This famously occurred in Super Bowl XIII between the Pittsburgh Steelers and Dallas Cowboys, which American bookmakers still remember as Black Sunday. For that game, bookmakers opened Pittsburgh as a 3.5 point favorite, and the line closed just before kickoff at Pittsburgh -4.5. Pittsburgh won the game 35-31, enabling both those who took the Steelers -3.5 and those who wagered on the Cowboys +4.5 to collect.
Sometimes, a point spread is set at an amount that equals a common margin of victory for a particular sporting event. For instance, American football games are often decided by 3 points (the amount awarded for a field goal) or 7 points (the amount awarded for a touchdown with a successful extra-point attempt). In the case of a football game where the favorite is -7, moving the line up or down would likely result in a middle if the favorite wins by exactly 7 points. In this situation, the bookmaker may choose to adjust the return in response to unbalanced action, rather than move the point spread. If the 7 point favorite is getting the most wagers, a bookmaker may reduce the winning return on that team from -7 (-110) to -7 (-120), and increase the winning return on the opposing team from +7 (-110) to +7 (+100). Once this occurs, bettors looking to wager on the favorite will only get a return of $100 for every $120 wagered, while underdog players will get a return of even money for every dollar they wager. The house edge, or vigorish, does not materially change in this instance.
A bookmaker's line can be influenced by one or several large wagers made on a match. Bookmakers pay particular attention to the bets of a professional sports gambler, commonly known within the industry as a "sharp" or "wiseguy." Most bookmakers will not accept bets from bettors they believe fit in this category or otherwise severely restrict how much they are able to stake. Professionals evade such efforts by hiring agents known as "beards" to place bets on their behalf. Groups of professionals who work together are known as a "syndicate." These syndicates will often place large wagers with several books simultaneously, causing the prices to move quickly. Observers refer to these fast line movements as "steam."
Conversely, bettors who are primarily recreational are referred to as "squares". Online, there are certain betting shops that cater more towards sharps and those toward squares. Shops that cater towards professionals generally have higher (or no) upper betting limits and offer lower vigorish, while making some of the money back on fees for withdrawals or minimum bets. Meanwhile, "square" shops generally have lower betting limits and offer more signup bonuses. In return, they charge the standard 11-to-10 vigorish, and offer worse moneylines than the "sharp" shops. In many of the minor sports, sharps make up the majority of bettors, while for large public sporting events such as the NCAA Men's Division I Basketball Championship and the Super Bowl, recreational bettors make up almost 90% of the betting action at sportsbooks, and are the top betting events both in Nevada and online.[1]
Because of how lines move quickly during sporting events, arbitrage betting is possible. Theoretically, this will guarantee a small profit of 1-5% when a person bets on one line at one shop and on the opposite line at another shop. However, a large sum of capital is required for the amount of reward, and great care must be exercised to avoid accidentally betting on the same side at both shops.
Arbitrage situations are commonly found during halftime and intermission periods, where there is a limited amount of time for each bookmaker to determine the line and accept bets. Arbitrage betting is also possible in the weeks and days prior to sporting events as betting lines, especially for American football, are generally set early in a given time period and then adjusted in reaction to betting patterns and other relevant information as the time of the game approaches. Savvy gamblers will sometimes be able to place an early bet using the initial line and a late bet using the later line and then hope that the actual result of the contest falls somewhere between the two bets, thus ensuring either a large win or zero losses.
With the advent of online gambling came odds comparison sites that highlighted arbitrage opportunities by displaying the realtime prices of a number of bookmakers alongside each other. These sites continue to provide the most crucial information to professionals and casual gamblers alike who are looking to bet at the best odds. Also, the above-described practice of dual lines is very common with online bookmakers, and as such may increase arbitrage opportunities.
In general, all forms of arbitrage betting is commonly known as "middling" or "finding the middle" of a particular contest and were fairly common in the early days of organized sports gambling. However, the relatively recent advent of both better communications between the individual sports books, the internet, and more sophisticated linesmaking techniques, has led to fewer opportunities for gamblers to make these types of bets. However with the plethora of new sports bet offerings (many of which are not effectively analyzed by the host bookmaker), arbitrage opportunities continue to exist.
The Federal Wire Act of 1961 was an attempt by the US government to prevent illegal bookmaking.