The parimutuel system is used in gambling on horse racing, greyhound racing, jai alai, and all sporting events of relatively short duration in which participants finish in a ranked order. A modified parimutuel system is also used in some lottery games.
Betting on the Favorite, an 1870 engraving
Parimutuel betting differs from fixed-odds betting in that the final payout is not determined until the pool is closed – in fixed odds betting, the payout is agreed at the time the bet is sold.
Parimutuel gambling is frequently state-regulated, and offered in many places where gambling is otherwise illegal. Parimutuel gambling is often also offered at "off track" facilities, where players may bet on the events without actually being present to observe them in person.
Example of parimutuel betting
Consider a hypothetical event which has 8 possible outcomes, in a country using a decimal currency such as dollars. Each outcome has a certain amount of money wagered:
Thus the total pool of money on the event is $514.00. Following the start of the event, no more wagers are accepted. The event is decided and the winning outcome is determined to be Outcome 4 with $55.00 wagered. The payout is now calculated. First the commission or take for the wagering company is deducted from the pool, for example with a commission rate of 14.25% the calculation is: $514 × (1 - 0.1425) = $440.76. The remaining amount in the pool is now distributed to those who wagered on Outcome 4: $440.76 / $55 ≈ $8 per $1 wagered. This payout includes the $1 wagered plus an additional $7 profit. Thus, the odds on Outcome 4 are 7-to-1 (or, expressed as decimal odds, 8).
Often at certain times prior to the event, betting agencies will provide approximates for what should be paid out for a given outcome should no more bets be accepted at the current time. Using the wagers and commission rate above (14.25%), an approximates table in decimal odds would be:
In real-life examples such as horse racing, the pool size often extends into millions of dollars with many different types of outcomes (winning horses) and complex commission calculations.
Sometimes the amounts paid out are rounded down to a denomination interval—in the United States and Australia, 10¢ intervals are used. The rounding loss is sometimes known as breakage and is retained by the betting agency as part of the commission.
The above description of the mechanics of parimutuel wagering would suggest that it is impossible for the wagering company (the "house") to lose money, as the commission is deducted before the payouts are calculated. However, in rare circumstances, it is possible for the house to lose money on an event. This situation can occur when there are legal requirements for minimum winning payouts (for example, there may be a legal requirement to pay at least $1.10 on a winning one dollar wager). If the minimum legal winning payout exceeds the payout computed by the standard parimutuel mathematics by a sufficient amount, the house might lose money on this set of wagers.
In horse racing, a practical example of this circumstance might be when an overwhelming favorite wins. The parimutuel calculation results might call for a very small winning payout (say, $1.02 or $1.03 on a dollar bet), but the legal regulation would require a larger payout (e.g., $1.10 on a dollar bet). In North America, this condition is usually referred to as a minus pool.
In an event with a set of n possible outcomes, with wagers W1, W2, …, Wn the total pool of money on the event is
After the wagering company deducts a commission rate of r from the pool, the amount remaining to be distributed between the successful bettors is WR = WT(1 − r). Those who bet on the successful outcome m will receive a payout of WR / Wm for every dollar they bet on it.
History of parimutuel betting
The parimutuel system was invented by Catalan impresario Joseph Oller in 1867.
The large amount of calculation involved in this system led to the invention of a specialized mechanical calculating machine known as a totalisator, "automatic totalisator" or "tote board", invented by the Australian engineer, George Alfred Julius. The first was installed at Ellerslie Racecourse, Auckland, New Zealand in 1913, and they came into widespread use at race courses throughout the world. The U.S. introduction was in 1927, which led to the opening of the suburban Arlington Racetrack in Arlington Park, near Chicago and Sportsman's Pack in Cicero, Illinois, in 1932.
Parimutuel bet types
There may be several different types of bets, in which case each type of bet has its own pool. The basic bets involve predicting the order of finish for a single participant, as follows:
In Canada and the United States, the most common types of bet on horse races include:
* Win – to succeed the bettor must pick the horse that wins the race
* Place – the bettor must pick a horse that finishes either first or second
* Show – the bettor must pick a horse that finishes first, second or third
* Exacta, perfecta, or exactor – the bettor must pick the two horses that finish first and second, in the exact order
* Trifecta or triactor – the bettor must pick the three horses that finish first, second, and third, in the exact order
* Superfecta – the bettor must pick the four horses that finish first, second, third and fourth, in the exact order
* Box – a box can be placed around exotic betting types such as exacta, trifecta or superfecta bets. This places a bet for all permutations of the numbers in the box. An exacta box with 2 numbers, commonly called quinella or quiniela, is a bet on either of two permutations: A first and B second, or B first and A second. A trifecta box with 3 numbers has 6 possible permutations (of the horses in the 'box' 3 can finish first, 2 can finish second, and one can finish third, 3 × 2 × 1) and costs 6 times the betting base amount. A trifecta box with 5 numbers has 60 possible permutations and costs 60 times the betting base amount (5 × 4 × 3). In France, a 'box' gives only the ordered permutations going along an ordered list of numbers such that a trifecta box with 6 numbers would cost 20 times the base amount
* Any2 or Duet – The bettor must pick the 2 horses who will place first, second or third but can finish in any order. This could be thought of as a double horse show key (see below)
* Double – the bettor must pick the winners of two successive races (a 'running' or 'rolling' double); most race tracks in Canada and the United States take double wagers on the first two races on the program (the daily double) and on the last two (the late double)
* Triple – the bettor must pick the winners of three successive races; like doubles, many tracks offer 'running' or 'rolling' triples. Also called pick three or more commonly, a treble
* Quadrella or Quaddie – The bettor must pick the winners of four nominated races at the same track
* Sweep – the bettor must pick the winners of four or more successive races. In the US, this is usually called pick four and pick six, with the latter paying out a consolation return to bettors correctly selecting five winners out of six races, and with "rollover" jackpots accumulating each day until one or more bettors correctly picks all six winners
Win, place and show wagers class as straight bets, and the remaining wagers as exotic bets. Bettors usually make multiple wagers on exotic bets. A box consists of a multiple wager in which bettors bet all possible combinations of a group of horses in the same race. A key involves making a multiple wager with a single horse in one race bet in one position with all possible combinations of other selected horses in a single race. A wheel consists of betting all horses in one race of a bet involving two or more races. For example a 1-all daily double wheel bets the 1-horse in the first race with every horse in the second.
People making straight bets commonly employ the strategy of an 'each way' bet. Here the bettor picks a horse and bets it will win, and makes an additional bet that it will show, so that theoretically if the horse runs third it will at least pay back the two bets. The Canadian and American equivalent is the bet across (short for across the board): the bettor bets equal sums on the horse to win, place, and show.
In Canada and the United States bettors make exotic wagers on horses running at the same track on the same program. In the United Kingdom bookmakers offer exotic wagers on horses at different tracks. Probably the Yankee occurs most commonly: in this the bettor tries to pick the winner of four races. This bet also includes subsidiary wagers on smaller combinations of the chosen horses; for example, if only two of the four horses win, the bettor still collects for their double. A Trixie requires trying to pick three winners, and a Canadian or Super Yankee trying to pick five; these also include subsidiary bets. The term nap identifies the best bet of the day.
A parlay or accumulator consists of a series of bets in which bettors stake the winnings from one race on the next in order until either the bettor loses or the series completes successfully.
* Win - Runner must finish first
* Place - Runner must finish first, second or third place (In events with five to seven runners, no dividends are payable on third place. ("NTD" or No Third Dividend) and in events with 4 or fewer runners, only Win betting is allowed)
* Each-Way - A combination of Win and Place. A $5 bet Each-way is a $5.00 bet to Win and a $5.00 bet to Place, for a total bet cost of $10
* Exacta – The bettor must correctly pick the two runners which finish first and second
* Quinella – The bettor must pick the two runners which finish first and second, but need not specify which will finish first
* Trifecta - The bettor must correctly pick the three runners which finish first, second, and third
* First4 – The bettor must correctly pick the four runners which finish first, second, third and fourth
* Duet - The bettor must pick the 2 horses who will place first, second or third but can finish in any order
* Running Double – The bettor must pick the winners of two consecutive races at same track
* Daily Double – The bettor must pick the winners of two nominated races at the same track
* Treble – The bettor must pick the winners of three nominated races at the same track. This bet type is only available in the states of Queensland and South Australia
* Quadrella or Quaddie – The bettor must pick the winners of four nominated races at the same track
* Big 6 – The bettor must pick the winners of six nominated races, which can be at the same track or split over two or more tracks
In Australia, certain exotic bet types can be laid as "flexi" bets. Usually the price of an exotic bet is determined by a set multiple of the outcome, for example $60 for a five horse boxed trifecta at one unit ($1) - or $30 at half unit (50c). If the bet is successful, the bettor will get either the full winning amount shown on the board, or half the winning amount. Under a flexi system the bettor can nominate their desired total wager, and their percentage of payout is determined by this wager's relationship to the full unit price. Using a five horse box trifecta, the bettor may wish to lay only $20 on the outcome. Their percentage of winnings is now calculated as $20/$60 = 33.3%. If the bet is successful, the payout will be 33.3% of the winning amount for a full unit bet.
In recent times the 'Roving Banker' variant for Trifecta and First4 betting is now offered. For a Roving Banker First4 select one, two or three runners that you believe will definitely finish 1st, 2nd, 3rd or 4th. Choose up to 3 selections as Roving Banker(s) with other runners to fill the remaining place(s). A Roving Banker Trifecta is where you believe that one or two runners will definitely finish 1st, 2nd or 3rd. You can place your bet by picking your favourite runner to finish in any place within your bet and complete the Trifecta with any number of other runners to fill the other placing(s).
The following pools are operated at meetings in mainland Britain:
* Win - Runner must finish first
* Place - Runner must finish within the first two places (in a 5-7 runner race), three places (8-15 runners and non-handicaps with 16+ runners) or four places (handicaps with 16+ runners)
* Each-way - Charged and settled as one bet to win and another bet to place (for example, a punter asking for a bet of "five pounds each way" will be expected to pay ten pounds)
* Scoop6 - On Saturdays only
* Jackpot - Pick 6
* Trifecta - The bettor must correctly pick the three runners which finish first, second, and third, in the correct order.
Tote Ireland operates the following pools:
* Win - Runner must finish first
* Place - Runner must finish within the first two places (in a 5-7 runner race), three places (8-15 runners and non-handicaps with 16+ runners) or four places (handicaps with 16+ runners). (From 23 April 2000 to 23 May 2010, Tote Ireland operated 4-place betting on ALL races with 16 or more runners.)
* Each-way - Charged and settled as one bet to win and another bet to place (for example, a punter asking for a bet of "five euro each way" will be expected to pay ten euro.)
* Jackpot - A Pick 4 bet on races 3-6 at every meeting
* Pick Six - On races 1-6 at one meeting on all Sundays and occasionally on other days (introduced on 9 January 2011).
* Placepot - The better must correctly pick one horse to place in each of the races 2-7.
* Exacta - The bettor must correctly pick the two runners which finish first and second, in the correct order.
* Trifecta - The bettor must correctly pick the three runners which finish first, second, and third, in the correct order (introduced on 26 May 2010).
* Daily Double - The bettor must correctly pick the winners of race 5 and race 6 (introduced on 22 January 2011).
Different arrangements apply at the two recognised racecourses in Northern Ireland. Tote Ireland operates pools on racing at Down Royal, but at Downpatrick the tote pools are operated independently by Datatote who also run all greyhound pools in Ireland and most greyhound pools in the UK.
Bet types for harness racing (trotting):
* Vinnare (winner) - Runner must finish first
* Plats (place) - Runner must finish within the first two places (up to 5 runners) or first three places (6 runners or more)
* Vinnare & Plats - Two bets, one on "vinnare" and one on "plats" for the same runner. Asking for a bet of "50 SEK vinnare och plats" costs 100 SEK
* Tvilling (twin) - The bettor must pick the runners that finish first and second, but need not specify which will finish first
* Trio (trio) - The bettor must pick the runners that finish first, second and third in a nominated race
* Dagens Dubbel (daily double) and Lunchdubbel (lunch double) - The bettor must pick the winners of two nominated races at the same track
* V3 - The bettor must pick the winners of three nominated races at the same track. Unlike V4, V5, V65 and V75, where a bet for all races must be made before the start of the first race, in V3 the bettor selects the winner one race at a time
* V4 - The bettor must pick the winners of four nominated races at the same track
* V5 - The bettor must pick the winners of five nominated races at the same track
* V65 - The bettor must pick the winners of six nominated races at the same track. Return is also given for (combinations of) five correctly picked winners, even if the same bet included all the six winners
* V64 - The bettor must pick the winners of six nominated races at the same track. Return is also given for (combinations of) five or four correctly picked winners, even if the same bet included more correct picks
* V75 - The bettor must pick the winners of seven nominated races at the same track. Return is also given for (combinations of) six or five winners picked correctly, even if the same bet included more correct picks. The betting pool is split into three separate pools for all combinations of seven (40%), six (20%) and five (40%) correctly picked winners. This is the largest nationwide betting game in Sweden, running each Saturday with weekly pools of about 80 MSEK ($11 million)
Strategy and comparison with independent bookmakers
Unlike many forms of casino gambling, in parimutuel betting the gambler bets against other gamblers, not the house. The science of determining the outcome of a race is called handicapping.
It is possible for a skilled player to win money in the long run at this type of gambling, but overcoming the deficit produced by taxes, the facility's take, and the breakage is difficult to accomplish and few people are successful at it.
Independent off-track bookmakers have a smaller take and thus offer better payoffs, but they are illegal in some countries. However, with the introduction of Internet gambling has come "rebate shops". These off-shore betting shops in fact return some percentage of every bet made to the bettor. They are in effect reducing their take from 15-18% to as little as 1 or 2%, still ensuring a profit as they operate with minimal overhead. Rebate shops allow skilled horse players to make a steady income.
The recent WTO decision DS285 against the United States of America by the small island nation of Antigua opens the possibility for offshore horse betting groups to compete legally with parimutuel betting groups.