bet sportsbook

An over-under or over/under bet is a wager in which a sportsbook will predict a number for a statistic in a given game (usually the combined score of the two teams), and bettors wager that the actual number in the game will be either higher or lower than that number. For example, in Super Bowl XXXIX, most Las Vegas casinos set the over-under for the score of the game at 46.0. A bettor could wager that the combined score of the two teams would be either more than or less than that number (as it happened, the combined score was 45, so anyone who had bet the under wonThe goal of a sportsbook manager is to have an equal number of bets on both sides of the over-under. In theory, this means that the manager could set the value at zero and then readjust based on either the number of incoming bets and/or events that influence the potential outcome. In practice, the initial value is based on both quantitative (e.g. win loss record, average points per game etc) and subjective information (e.g. media reports, mental status of players etc)
In Las Vegas over-under bets, the value changes automatically by half a point based on each $1,000 bet.
For example, if the current over-under is 5 and a bet for $1,000 over comes in, the value is adjusted to 5.5.
As another example, if the current over-under is 6 and an over bet for $20,000 comes in and an under bet for $18,000 comes in, the value would move to 7 ($20,000 - $18,000 = $2,000).
Though this bet is most commonly made with the combined score of the two teams, many other statistics can be used, including:
A team's win-loss record for the season In American football, a player's or team's total rushing yards or attempts, down conversions (first or third), interceptions, completions, etc. In basketball, a player's or team's total assists, blocks, turnovers, steals, field goal percentage, etc. In baseball, a player's or team's total number of home runs, RBI, etc. ESPN talk show Pardon the Interruption commonly features a segment called Over/Under in which the hosts, Tony Kornheiser and Michael Wilbon will debate the over-under for certain statistics, some of them being particularly obscure and off-beat (such as the duration of a particular celebrity marriage). Retrieved from Spread betting is any of various types of wagering on the outcome of an event, where the pay-off is based on the accuracy of the wager, rather than a simple "win or lose" outcome, which is known as money-line betting. A spread is a range of outcomes, and the bet is whether the outcome will be above or below the spread. Spread betting has been a major growth market in the UK in recent years, with the number of gamblers heading towards one million.[1] As with all gambling, however, spread betting carries a high level of risk.[2] In the UK, spread betting is regulated by the Financial Services Authority rather than the Gambling CommissionThe general purpose of spread betting is to create an active market for both sides of a wager, even if the outcome of an event may appear a priori to be biased towards one side or the other. In a sporting event, for example, a strong team may be pitted against a historically weaker team. Persons betting on the event normally would be likely to favor the better team, to such an extent that there would be very few, if any, betting on the team perceived to be worse.
The use of a "point spread" evens out the market towards an equal number of participants on each side of the wager. This allows a bookmaker to make a market by accepting wagers on both sides of the spread. The bookmaker charges a commission and acts as the counterparty for each participant. As long as the number of participants on each side is roughly equal, the bookmaker is unconcerned with the actual outcome; profits instead come from the commissions.
Spread betting was invented by Charles K. McNeil, a mathematics teacher from Connecticut who became a bookmaker in Chicago in the 1940s.[4] The idea became popular in the United Kingdom in the 1980s. In North America, the gambler usually wagers that the difference between the scores of two teams will be less than or greater than the value specified by the bookmaker. An example:
The bookmaker advertises a spread of 4 points in a certain game; If the gambler bets on the "underdog", he is said to take the points and will win if the underdog's score plus the spread is greater than the favourite's score. The eventual score is Underdog 8, Favourite 10: 8 + 4 > 10, so the gambler wins; The eventual score is Underdog 8, Favourite 13: 8 + 4 <> 4, so the gambler wins; The eventual score is Underdog 8, Favourite 10: 10 - 4 < 8, so the gambler loses. Spreads may be specified in half-point fractions to avoid ties, or pushes. In the event of a tie after factoring in the point spread, the game is considered no action, and no money is won or lost.[5]
The winner of a North American spread bet wins his stake, while a losing gambler loses the stake plus the bookmaker's commission (commonly known as the vigorish or vig, usually 10% of the stake); a push is treated as if no bet had been made. In the United Kingdom both sides play at odds of 9/10 and "dead heat" rules apply, resulting in a net loss of £5 on a £100 wager, due to the 9/10 odds of the proposition. If a key player on a side is injured and may not play, the bookmaker may refuse to accept bets by not quoting a spread on the event, or may "circle" the game; in this case, lower maximum amounts for each bet are enforced (typically $5,000 instead of the $25,000 limit observed at most Las Vegas sports books) and certain specialty wagers, such as "teasers", are prohibited.
A teaser is a bet that alters the spread in the gambler's favor by a predetermined margin, often six points— for example, if the line is 3.5 points and the bettor wants to place a teaser bet on the underdog, he takes 9.5 points instead; a teaser bet on the favorite would mean that the gambler takes 2.5 points instead of having to give the 3.5. In return for the additional points, the payout if the gambler wins is less than even money. At some establishments, the "reverse teaser" also exists, which alters the spread against the gambler, who gets paid at more than evens if the bet wins. Example: In a soccer match the bookmaker believes that 12 or 13 corners will occur, thus the spread will be set at 12-13.
A gambler believes that there will be more than 13 corners, and 'buys' at £25 a point at 13. If the number of corners is 16, the gambler wins (16 - 13) = 3 x £25. If the number of corners is 10, the gambler loses (13 - 10) = 3 x £25. A 'sell' transaction is similar except that it is made against the bottom value of the spread. Often "live pricing" will change the spread during the course of an event, allowing a profit to be increased or a loss minimized. In North American sports betting many of these wagers would be classified as over-under (or, more commonly today, total) bets rather than spread bets. However, these are for one side or another of a total only, and do not increase the amount won or lost as the actual moves away from the bookmaker's prediction. Instead, over-under or total bets are handled much like point-spread bets on a team, with the usual 10/11 (4.55%) commission applied. Many Nevada sports books will allow these bets to be used in parlays, just like team point-spread bets, making it possible to bet, for instance, "the Packers and the over," and be paid if both the Packers "cover" the point spread and the total score is higher than the book's prediction. (Such parlays usually pay off at odds of 13:5 with no "vig," just as a standard two-team parlay would.)
In 2004 Cantor Fitzgerald launched the spread betting exchange Cantor Spreadfair, which matches up spread bettors opposing views and allows them to bet with each other. This removal of the faceless bookmaker allows clients to bet at the spread size and monetary level that they request, and in turn this creates a tighter spread margin, which in turn allows users to lose less and win more than with the non-exchange spread-betting firms.
The mathematical analysis of spreads and spread betting is a large and growing subject. For example, sports that have simple 1-point scoring systems (e.g., baseball, hockey, and soccer) may be analysed using Poisson and Skellam statistics.