Bets

A bet is a wager of something of value on the outcome of an uncertain event. The bettor promises to pay or give value if the event occurs, and the counterparty agrees to do the same if it does not. Bets are settled when the outcome is determined, and the amount won or lost is based on agreed odds or terms.

Bets come in various forms. Fixed-odds bets involve agreed odds at the time of wagering. Parlays combine multiple bets into a single stake. Spread betting uses a margin to exploit the predicted margin of victory. Prop bets, futures, and in-play or live bets place wagers on specific events or moments within an event. Some markets use pool or exchange formats.

Odds express the ratio of payoff to stake and can be presented as decimal, fractional, or moneyline formats. The expected value of a bet equals the probability of winning times the payoff minus the probability of losing times the stake. Bookmakers set margins, giving a long-run advantage to the house.

Gambling is regulated differently by jurisdiction. Licensed bookmakers, exchanges, and lotteries are common forms of licensed betting markets. Responsible gambling policies seek to prevent harms through self-exclusion, wagering limits, and support services.

Historically, betting appears in ancient civilizations and evolved with formal odds and bookmakers in the modern era. The rise of online betting and exchanges expanded access, while statistical models and data analytics influenced strategy and market efficiency.