Markets and selections
A sportsbook organises what it offers into events (a match, a race, a tournament), markets (a question about the event with a defined set of outcomes) and selections (the individual outcomes a customer can back). A Premier League fixture is one event with a long list of markets; the match result market has three selections; the total goals market has two per line. Learning the standard markets is learning the product.
The core markets
Match result, or 1X2. Home win, draw, away win. The standard football market and the reference for most others. In sports without draws it collapses to a two-way moneyline: which side wins.
Handicap and spread. One side is given a notional head start to even up an uneven contest. A football side at -1.5 must win by two or more for the bet to win; a basketball team at +6.5 can lose by six and still cover. Asian handicaps use quarter and half lines to remove or split the draw; a bet at -0.25 is half a bet at 0 and half at -0.5, so an exact draw returns half the stake and the other half loses. Point spreads are a staple of American football and basketball betting.
Totals, or over/under. Whether a statistic (goals, points, corners, games) finishes above or below a line. Over 2.5 goals wins if three or more are scored. Lines set at a half avoid pushes; lines set at a whole number (over 2.0) return the stake if the total lands exactly on the line.
Both teams to score. A two-way market on whether each side scores at least once.
Correct score. The exact final score. A multi-outcome market with long odds on most selections.
Outright, or futures. Who wins the tournament, the league, the title. Priced months ahead, settled at the end of the competition, often with "each-way" terms in racing and golf that pay a fraction of the odds for a placed finish.
Props, or proposition bets. Markets on things within the event: which player scores first, how many cards, who wins the toss, a player's points total. Player props are central to the American offer and are often combined into the same-game parlays described below.
In-play, or live. Any of the above, offered while the event is running, with the price updating as it goes. Sportradar's 2025 annual report says in-play accounts for the majority of gross gaming revenue in the more developed European markets. It is not allowed everywhere: Australia's Interactive Gambling Act bans online in-play sports betting.
Combining bets
Singles are one selection. Doubles, trebles and accumulators (parlays in America) combine two, three or more selections from different events; all must win. The odds multiply, which is why a small stake can produce a large payout and why the bookmaker's margin compounds.
System bets cover every combination within a set of selections. A Trixie is three selections in three doubles and a treble (four bets); a Yankee is four selections in six doubles, four trebles and a fourfold (eleven bets). They can pay out when only some selections win (at least two, for a Trixie or a Yankee), at the cost of a larger total stake.
Same-game parlays, or bet builders, combine selections from one event: a team to win, a player to score, over 2.5 goals. Because the outcomes are related, they cannot be priced by multiplying, and the price the book quotes is built from a model of the whole match. Ordinary multiples forbid this kind of "related contingency" for the same reason. Flutter's 2025 annual report describes same-game parlays as higher-margin bet types and credits its pricing and risk capabilities and rising same-game parlay penetration with lifting the structural revenue margin of its US sportsbook to 14.2% in fiscal 2025.
Racing markets
Horse and greyhound racing have their own conventions. Win and each-way (a win bet plus a place bet at a fraction of the odds) are the basics. Starting price (SP) is the official price at the off, which many bets are settled at; for British horseracing an independent body, the Starting Price Regulatory Commission, oversees how it is returned. Forecasts and tricasts pick the first two or three in order. Ante-post bets are placed days or weeks before the race, before the final declarations, with the risk that the horse does not run and the stake is lost. Racing also introduced Rule 4, a deduction from the winnings of bets struck at a price before a runner was withdrawn, which lesson four covers.
Exchanges and pools
Two models sit alongside the traditional bookmaker.
A betting exchange lets customers bet against each other. One customer backs an outcome; another lays it (bets it will not happen), acting as the bookmaker for that bet. The exchange charges a commission on customers' winnings rather than building a margin into the price. In Britain the Gambling Act 2005 treats an exchange as a betting intermediary, a service that facilitates bets between others. Exchanges offer the ability to lay, which bookmakers do not, and they are where sharp bettors and traders operate, so their prices are watched by the whole industry.
Pool, pari-mutuel or tote betting pools all stakes on an event, deducts a percentage, and shares the rest among winners in proportion to their stakes; the Gambling Act 2005 defines pool betting by winnings determined by the aggregate of stakes or divided among the winners. There are no fixed odds; the payout depends on how much was bet on each outcome. Racing totes, including American pari-mutuel racing, work this way.
Prediction markets
A newer category: exchanges where customers trade contracts that pay out on the outcome of an event, including sporting events, regulated in the United States as derivatives rather than as gambling. The Commodity Futures Trading Commission describes them as event contracts, often yes or no contracts with a fixed payout, usually $1, and its position is that under federal law they can operate in all 50 states. They function like betting exchanges with a different legal wrapper, and the industry is watching them closely because they can reach places sports betting cannot. That reach is contested: Flutter, which launched its own prediction markets app in December 2025, reports that these products have been subject to regulatory scrutiny and litigation.
What a product team thinks about
Each market has a settlement rule, a price source, a margin target, a stake limit and a set of risk controls, and adding a new market type is not trivial. Bet builders in particular need pricing models that account for how the legs are related. The next lesson goes inside the sportsbook to see how all of this is run on a match day.