Sports betting

Sports betting is the activity of predicting sports results and placing a wager on the outcome.

"}">

This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these messages) The examples and perspective in this article may not represent a worldwide view of the subject. (June 2018) This article may be too technical for most readers to understand. (July 2020)

Sports bettors place their wagers either legally, through a bookmaker/sportsbook, or illegally through privately run enterprises referred to as "bookies". The term "book" is a reference to the books used by wage brokers to track wagers, payouts, and debts. Many legal sportsbooks are found online, operated over the Internet from jurisdictions separate from the clients they serve, usually to get around various gambling laws (such as the Unlawful Internet Gambling Enforcement Act of 2006 in the United States) in select markets, such as Las Vegas, or on gambling cruises through self-serve kiosks.^[1] There are different types of legalized sports betting now such as game betting, parlays props and future bets. They take bets "up-front", meaning the bettor must pay the sportsbook before placing the bet. Due to the nature of their business, illegal bookies can operate anywhere but only require money from losing bettors and do not require the wagered money up front, creating the possibility of debt to the bookie from the bettor. This creates a number of other criminal elements, thus furthering their illegality.

There have been a number of sports betting scandals, affecting the integrity of sports events through various acts including point shaving (players affecting the score by missing shots), spot-fixing (a player action is fixed), bad calls from officials at key moments, and overall match-fixing (the overall result of the event is fixed). Examples include the 1919 World Series, the alleged (and later admitted) illegal gambling of former baseball player Pete Rose, and former NBA referee Tim Donaghy.

This section needs additional citations for verification. (August 2020)

This is a list of sports bet types common to the United States.

• Moneyline bets do not have a spread or handicap, and require the chosen team to win the game outright. The favored team pays lower odds than does the underdog; thus, it acts mainly as an enticement to take the underdog for a better payout. Sometimes a bettor may couple this type of bet on the favored team to increase the payout of a parlay.
• Spread betting are wagers that are made against the spread. The spread, or line, is a number assigned by the bookmakers which handicaps one team and favors another when two teams play each other and one is perceived as being more likely to win. The favorite "gives" points from the final score, and the underdog "takes" points. This number can also be in increments of half-a-point (.5) even though very few sports have .5 point scoring (i.e., The Ryder Cup), to avoid the possibility of a tie.

For example, before game 5 of the 2012 NBA Finals, the Miami Heat were expected to beat the Oklahoma City Thunder. The line read: Miami −3.5, Oklahoma City +3.5.^[2] To determine who wins against the spread, the line is either added or subtracted from a team's final score. In the above example, if the bettor chose Miami, for him to win his bet, Miami would have to win the game by 4 points or more. If a bettor took Oklahoma City, they would have to win outright or lose by 3 points or fewer.

If the final adjusted score is a tie, the bet is considered a push. The half point at the end is sometimes added to eliminate the possibility of a push. This is the most common type of bet in American sports betting.

• Total (Over/Under) bets are wagers made based on the total score between both teams. In an example, if an MLB game has a total of 10.5, an over bettor will want the combined total to be greater, and the opposite for a bettor taking the under. If the combined total is the same as the proposed total, the bet is a push. Most sports books refund all wagers on pushes, though a minority counts them as losses.
• Proposition bets are wagers made on a very specific outcome of a match not related to the final score, usually of a statistical nature. Examples include predicting the number of goals a star player scores in an association football match, betting whether a player will run for a certain number of yards in an American football game, 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 that rewards successful bettors with a greater payout only if all bets in the parlay win. A parlay is at least two bets, but can be as many as the bookmaker will allow.

The possible payout of the parlay is determined by the combined likelihood of all bets placed. A parlay of riskier bets (more underdogs) will pay greater than a parlay of more likely bets (more favorites). In a parlay, all bets need to win in order for the parlay to win. If one of the bets on a parlay loses, the whole parlay loses. In the event of a push, the pushed bet would be taken out of the parlay and the parlay would bump down to a set of odds without that bet.

Parlays are very appealing to bettors because they pay out much more than the total winnings of their constituent straight bets. However, it is much more difficult to hit on a parlay than it is on a single wager. In the USA, parlays account for upward of 70% of each state's total sportsbook revenue each month.^[3]

• Teasers. A teaser is a parlay that gives the bettor an advantage at a lower, but still positive, payout if successful.

The bettor selects the sport(s), number of games, and number of points given.

If the bettor takes two NBA games at +6.5 it will adjust the individual bets at that rate. So a bet on a 3-point underdog at +3 will become a bet at +9.5 points, and for favorites, it will change a 3-point favorite at −3 to +3.5 points.

Although the rules to win his bet are the same as a parlay, he is paid less than a regular parlay due to the increased odds of winning.

• If bets. An if bet consists of at least two straight bets joined by an if clause, which determines the wager process. If the player's first selection complies with the condition (clause), then the second selection will have action; if the second selection complies with the condition, then the third selection will have action and so on.
• Run line, puck line, or goal line bets. These are wagers offered as alternatives to money line wagers in baseball, hockey, or soccer, respectively. These bets are effectively point spread bets that have the same money line odds on either side of the wager (i.e., industry standard of −110 to −115). Sportsbooks will occasionally shift the moneyline by a few points on either side of these spread bets.
• Futures wagers. While all sports wagers are by definition on future events, bets listed as "futures" generally have a long-term horizon measured in weeks or months; for example, a bet that a certain NFL team will win the Super Bowl for the upcoming season. Such a bet can be made before the season starts in September for the best possible payout, but futures are typically available year-round, with payouts being reduced as the season progresses and it becomes easier to predict a champion. In this example, winning bets will not pay off until the conclusion of the Super Bowl in January or February (although many of the losing bets will be clear well before then and can be closed out by the book). 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 (or +5000) to win the Super Bowl, which means that the bet will pay 50 times the amount wagered if the team does so. In general, most sportsbooks will prefer this type of wager due to the low win-probability, and also the longer period of time in which the house holds the player's money while the bet is pending. For this same reason, most professional bettors do not prefer to place futures bets.

A sportsbook may choose to buy in-play futures wagers at a price below the actual payout before a championship is decided if the potential payout is very high (and thus, damaging to the sportsbook due to the money that may be lost). The most recent example of this was when Leicester City pursued and went on to win the 2015/16 Premier League.^[4]

• Head-to-Head. In these bets, bettor predicts competitors results against each other and not on the overall result of the event. One example are Formula One races, where you bet on two or three drivers and their placement among the others. Sometimes you can also bet a "tie", in which one or both drivers either have the same time, drop out, or get disqualified.
• Totalizators. In totalizators (sometimes called flexible-rate bets) the odds are changing in real-time according to the share of total exchange each of the possible outcomes have received taking into account the return rate of the bookmaker offering the bet. For example: If the bookmakers return percentage is 90%, 90% of the amount placed on the winning result will be given back to bettors and 10% goes to the bookmaker. Naturally the more money bet on a certain result, the smaller the odds on that outcome become. This is similar to parimutuel wagering in horse racing and dog racing.
• Half bets. A half (halftime) bet applies only to the score of the first or second half. This bet can be placed on the spread (line) or over/under. This can also be applied to a specific quarter in American football or basketball, a fewer number of innings in baseball, or a specific period in hockey.
• In-play betting. In-play betting, or live betting, is a fairly new feature offered by some online sports books that enables bettors to place new bets while a sporting event is in progress. In-play betting first appeared towards the end of the 1990s when some bookmakers would take bets over the telephone whilst a sports event was in progress, and has now evolved into a popular online service in many countries.^[5] The introduction of in-play betting has allowed bookmakers to increase the number of markets available to bet on during sports events, and gamblers are able to place bets based on many types of in-game activity during the matches. For example, in football matches, it is possible to bet in on in-play markets including the match result, half-time score, number of goals scored in the first or second half of the game, the number of yellow cards during the match, and the name of the goal scorers.^[5] The availability of a particular sport and in-play markets varies from bookmaker to bookmaker. In-play sports betting has structural characteristics that have changed the mechanics of gambling for sports bettors, as they can now place a larger number of bets during a single sports game (as opposed to a single bet on who is going to win). One of the most important differences between being able to place an in-running sports bet opposed to a pre-match bet is that the nature of the market has been turned what was previously a discontinuous form of gambling into a continuous one. The gambling study literature has suggested that in-play sports betting may offer more of a risk to problem gamblers because it allows the option for high-speed continuous betting and requires rapid and impulsive decisions in the absence of time for reflection.^[5] There are three different types of in-play sports betting products(cash out, Edit my Acca, and Edit my Bet).

• Cash Out. Cash Out betting functionality lets the user of a betting website take profit early if their bet is coming in, or get some of their stake back if their bet is going against them—all before the event is over. Cash Out offers are optionally made by the website in real time on some current bets held by the user and are optionally taken by the user by clicking on a button on the webpage to "Cash out". Cash Out sports betting functionality developed on digital betting websites after 2008 with the evolution of betting exchanges. It was later adopted by online sports books and suppliers of betting software. 'Cash out' is offered to users by online sportsbook operators based on the profitability of offering the option to the user to divest their existing bet on an outcome and is sometimes available on singles and multiples. It is regularly offered on a wide range of sports, including American football, tennis, horse racing, basketball, and most other markets. You can Cash Out of bets pre-play, in-play, and between legs, before the outcome of the event. It has proved a key customer retention tool for sports book operators looking to capitalize on the use of mobile handsets while the bettor/user is also watching a given event.^[5]
• Edit My Acca. This feature allows gamblers to remove selections from their accumulator after the bet has been placed and in some instances after the selected event has started. The betting slip is then revised to feature the amended selections and a new potential return amount. This can be done online or via a mobile device.^[5]
• Edit My Bet. The "edit bet" feature can be used by gamblers to "unsettle straight accumulators" before matches have started or whilst they are in-play. The feature can also be used for to swap single bets for new bets, and the gambler is given a new bet selection valued at the bookie's cash out price to reflect live market/game odds for the original bet.^[5]

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.^[6] However, this Act does not apply to other types of online gambling.^[7] The Supreme Court has not ruled on the meaning of the Federal Wire Act as it pertains to online gambling.

Bookmakers usually hold an 11–10 advantage over their customers—for small wagers it is closer to a 6–5 advantage—so the bookmaker will most likely survive over the long term. Successful bookmakers must be able to withstand a large short term loss. (Boyd, 1981)

Many of the leading gambling bookmakers from the 1930s to the 1960s got their start during the prohibition era of the 1920s. They were often descendants of the influx of immigrants coming into the US at this time. Although the common stereotype is that these bookies were of Italian descent, many leading bookies were of eastern European ancestry.^[8]

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 is "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.

In Asian betting markets, other frequently used formats for expressing odds include Hong Kong, Malaysian, and Indonesian-style odds formats. Odds are also quite often expressed in terms of implied probability, which corresponds to the probability with which the event in question would need to occur for the bet to be a break-even proposition (on the average).

Many online tools also exist for automated conversion between these odds formats.

In setting odds, the bookmaker is subject to a number of limitations:^[9]

• The probability implied by the odds should be greater than the true probability for each possible outcome to guarantee positive expected profit.
• If the wagers on each outcome are made in ratio to the implied odds, then the bookmaker is guaranteed a profit (balanced book).

This section needs expansion. You can help by making an edit requestadding to it . (September 2023)

The examples and perspective in this section deal primarily with United States and do not represent a worldwide view of the subject. (September 2023)

In many countries, bookmaking (the profession of accepting sports wagers) is regulated but not criminalized.

The opinions of betting from sport authorities are mixed. The United States National Football League was previously fully against any sort of legalization of sports betting prior to the late 2010s, strongly protesting it as to not bring corruption into the game.^{[citation needed]} On the other hand, the CEO of the International Cricket Council believe sports betting, in particular in India, should be legalized to curb illegal bookies where match fixing has occurred from nontransparent bookmakers.^{[citation needed]} According to the Law Commission of India, all forms of gambling are illegal. Online sports betting is a gray area and is not banned by any particular law in the Indian legal system. That is because specific provisions distinguish between games of chance and games of skill.^{[citation needed]}

United States

Main article: Gambling in the United States § Sports betting

In the United States, it was previously illegal under the Professional and Amateur Sports Protection Act of 1992 (PASPA) for states to authorize legal sports betting, hence making it effectively illegal. The states of Delaware, Montana, Nevada, and Oregon—which had pre-existing sports lotteries and sports betting frameworks, were grandfathered in and exempted from the effects of the Act.^[11][12] PASPA was struck down by the Supreme Court in Murphy v. National Collegiate Athletic Association in 2018, paving the way for other states to legalize sports betting.

In May 2020, it was reported that since the Supreme Court's PASPA decision, over $20 billion had been spent on sports betting in the United States.^[13] As of January 2024, 37 states, Washington, D.C., and the territory of Puerto Rico have operational legalized sports betting, while North Carolina has legalized it though it sports betting operations will begin later in 2024. 30 states, Washington D.C. and Puerto Rico have also legalized online sports betting, though in 8 states that have legalized sports betting, betting can only occur through legal physical sportsbooks.^[14]

The positions of the four major American sports leagues (representing American football, baseball, basketball, and ice hockey) have become more complex since their decision to embrace daily fantasy sports (DFS) in 2014, which are described by those within the industry as "almost identical to a casino" in nature. With the contention by critics that such activities blur the lines between gambling and fantasy sports, the endorsement of all four major sports leagues and many individual franchises provided a marked contrast to their positions on betting.^[17] Professional sports leagues updated their positions again on May 14, 2018, when the Supreme Court of the United States overturned the Professional and Amateur Sports Protection Act of 1992 (PASPA).

Perhaps the most extreme ban on sports betting is imposed by the NCAA, the main governing body for U.S. college sports. The NCAA reified their position in the wake of various betting scandals, including two high-profile men's basketball episodes in the 1990s—the 1992 University of Nevada, Las Vegas and 1994 Arizona State University point shaving scandals.^[33][34] As states began legalizing sports betting in the late 2010s, the NCAA signaled a shift in tone. In 2017, then-NCAA President Mark Emmert talked about Las Vegas possibly hosting the NCAA Division I men's basketball tournament in the future.^[35]

Emmert acknowledged the Supreme Court's overturn of PASPA on May 14, 2018,^[36][37] restating the NCAA's strong commitment to competition and its student-athletes. "Our highest priorities in any conversation about sports wagering are maintaining the integrity of competition and student-athlete well-being." Emmert also emphasized the importance of proper federal regulation. "While we recognize the critical role of state governments, strong federal standards are necessary to safeguard the integrity of college sports and the athletes who play these games at all levels."^[38]

Three days after the Supreme Court ruling, the NCAA suspended its policy prohibiting championship events from being held in states with legal sports betting. The policy was fully rescinded in May 2019. In October 2020, Las Vegas was awarded the West Regional of the 2023 Division I men's basketball tournament; the Frozen Four, the final phase of the Division I men's hockey tournament, in 2026; and the men's basketball Final Four in 2028.^[39]

As of the 2021–22 school year, the official manuals for all three NCAA divisions still expressly ban a member institution's athletic department staff, non-athletic staff with responsibilities related to athletic activities, athletic conference staff, and student athletes from knowingly participating in sports wagering activities.^[40][41][42]

This ban covers all competitions, whether intercollegiate, amateur, or professional, as well as team practices, in any sport in which the NCAA conducts a championship, plus Division I FBS football (whose championships have never been operated by the NCAA) and all sports within the scope of the NCAA Emerging Sports for Women program.^[43] The only exception is traditional wagers between institutions, most commonly associated with rivalries or bowl games; according to the NCAA, "items wagered must be representative of the involved institutions or the states in which they are located".^[44]

The NCAA maintains that "Sports wagering has the potential to undermine the integrity of sports contests and jeopardizes the well-being of student-athletes and the intercollegiate athletics community. It also demeans the competition and competitors alike by spreading a message that is contrary to the purpose and meaning of 'sport.'"^[45]

In 1919, the Chicago White Sox faced the Cincinnati Reds in the World Series. This series would go down as one of the biggest sports scandals of all time. As the story goes, professional gambler Joseph Sullivan paid eight members of the White Sox (Oscar Felsch, Arnold Gandil, Shoeless Joe Jackson, Fred McMullin, Charles Risberg, George Weaver, and Claude Williams) around 10,000 dollars each to fix the World Series. All eight players were banned from playing professional baseball for the rest of their lives.^[50] Pete Rose, the all-time MLB leader in hits, was similarly banned from baseball in 1989 for betting on games while he was an MLB manager.

The rule against gambling in baseball is known as "Rule 21", which is publicly posted on dugout walls and states: "Any player, umpire, or club or league official or employee, who shall bet any sum whatsoever on any baseball game in connection with which the bettor has a duty to perform shall be declared permanently ineligible." People permanently banned from Major League Baseball are also forever banned from entry into the Baseball Hall of Fame, although most such people have been reinstated a few years later by a later Commissioner of Baseball. For instance, while Mickey Mantle and Willie Mays were both banned from baseball in 1983 after taking jobs as casino greeters, they were reinstated two years later.

A 1906 betting scandal between the Massillon Tigers and Canton Bulldogs, two of the top teams in professional American football in the early 1900s, led to the demise of "big-money" professional football for several years. Modern research has suggested that the claims of betting were unsubstantiated.

On December 7, 1980, the San Francisco 49ers overcame a halftime deficit of 28 points in what became the greatest regular season comeback victory in NFL regular season history. By the beginning of the third quarter, notorious Vegas bookmaker Frank Rosenthal received forfeiture notices from 246 San Francisco bettors totaling more than $25,000 in premature winnings. Rosenthal was able to retain these winnings despite the outcome of the game due to gambling regulations previously established by the NAGRA.^[51]

The Cronje Affair was an India-South Africa Cricket match fixing scandal that went public in 2000.^[52][53] It began in 1996 when the-then captain of the South African national cricket team, Hansie Cronje, was convinced by Mukesh "John" Gupta, an Indian bookmaker, to throw a match during a Test in Kanpur, India. The scheme was discovered when Delhi police recorded illegal dealings between Indian bookmaker Sanjay Chawla and Cronje. According to the Telegraph in 2010, Cronje was paid off a total of £65,000 from Gupta.^[54]

Corruption in tennis has been long considered as issue.^[55] In 2011, the former world No. 55 Austrian tennis player, Daniel Köllerer, became the first tennis player to be banned for life for attempting to fix matches. The violations were outstanding between October 2009 and July 2010 after The Tennis Integrity Units had launched an investigation on behalf of the International Tennis Federation and the ATP and WTA tours. In 2004 and 2006, Koellerer was banned for six months due to his bad behavior. In addition, in August 2010, he facilitated betting by placing odds for matches and had links for placing bets.^[56]

Machine learning models can make predictions in real time based on data from numerous disparate sources, such as player performance, weather, fan sentiment, etc. Some models have shown accuracy slightly higher than domain experts.^[57]