In the United States of America sports betting is commonly performed through a bookmaker or through various online Internet outlets. The many types of bets include:

  • Proposition bets are wagers made on a very specific outcome of a match. Examples include guessing the number of goals each team scores in a handball match, betting whether a player will score in a football game, or wagering that a baseball player on one team will accumulate more hits than another player on the opposing team.
  • Parlays involve multiple bets (usually up to 12) and will reward a successful bettor 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.
  • Progressive parlays. A progressive parlay involves multiple bets (usually up to 12) and rewards successful bettors with a large payout, though not as large as normal parlays. However in a progressive parlay, unlike a regular parlay, a reduced payout will still be made even should some of the bets lose.
  • Teasers. A teaser allows the bettor to combine his bets on two or more different games. The bettor can adjust the point spreads for the two games, but realizes a lower return on the bets in the event of a win.
  • If bets. An if bet consists of at least two straight bets joined together 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 straight-up/moneyline prices in baseball, hockey or soccer, respectively. These bets feature a fixed point spread that (usually) offers a higher payout for the favorite and a lower payout for the underdog (both in comparison to the moneyline).
  • Future 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 must be made before the season starts in September, and 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 to win the Super Bowl, which means that the bet will pay 50 times the amount wagered if the team does so.
  • 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.

Bookmaking

The general role of the bookmaker is to act 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.

Odds

Odds for different outcomes in single bet are presented either in European format (decimal odds), UK format (fractional odds), or American format (moneyline odds). European format (decimal odds) are favored 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 favored by British bookmakers. They are the ratio of the amount won to the stake. Fractional odds of 1/1 are an even bet. US format odds are favored in the United States. They 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.

Decimal Fractional US HongKong Indo Malay
1.50 1/2 -200 0.50 -2.00 0.50
2.00 1/1 +100 1.00 1.00 1.00
2.50 3/2 +150 1.50 1.50 -0.67
3.00 2/1 +200 2.00 2.00 -0.50

Conversion formulas

x To Do this
Decimal Fractional x-1 , then convert to fraction
Decimal US 100*(x-1) if x>=2; -100/(x-1) if x<2
Fractional Decimal divide fraction, then x+1
Fractional US divide fraction, then 100*x if x>=1; -100/x if x<1
US Decimal (x/100)+1 if x>0; (-100/x)+1 if x<0
US Fractional x/100, then convert to fraction if x>0; -100/x, then convert to fraction if x<0
Decimal HongKong x-1
HongKong Indo x if x>=1; (1/x)*-1 if x<1
HongKong Malay x if x<=1; (1/x)*-1 if X>1

In Asian betting markets, other frequently used formats for expressing odds include Hong Kong, Malay, 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 breakeven proposition (on the average).

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

Legality

In the USA it is illegal to operate a scheme except for in a few states. In many European nations bookmaking (the profession of accepting sports wagers) is regulated but not criminalized. The NCAA has threatened to ban all playoff games in Delaware if the state allows betting on college sports. New Jersey, which is also interested, has been similarly threatened. Interestingly for New Jersey, a Fairleigh Dickinson University PublicMind poll found in April 2009 that 63% of New Jerseyians supported legalizing sports betting in Atlantic city and at horse-racing tracks. However, only 48% of New Jersey voters approved of legalizing betting at off-track betting establishments. A slight majority of New Jersey voters (53%) also disapproved of legalizing sports betting nationally. 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. In the 2009 PublicMind poll, the possibility of corrupting sports was the main concern of New Jersey voters (54%) that opposed legalizing sports betting nationally. On the other hand, 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, many of which utilize sports information services.

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.