Prediction markets turn forecasts into tradable assets. You buy and sell contracts that pay out based on whether a specific event happens. The price of each contract reflects what the crowd thinks will happen. This system captures collective intelligence and often outperforms traditional polls. Understanding how these markets price events, settle trades, and resolve outcomes helps you read the signals they send about everything from elections to economic data.
The four moving parts: contracts, traders, oracle, settlement
Every prediction market has four core components. First, the contract defines the event and the payout. A binary contract might pay $1 if a candidate wins and $0 if they lose. Second, traders buy and sell these contracts based on their beliefs. Their collective trades set the market price. Third, an oracle determines the outcome when the event concludes. Platforms like Polymarket and Kalshi use trusted data sources or expert committees to verify results. Finally, settlement distributes payouts to winning positions and closes the market.
These four pieces work together to create a real-time probability feed. Traders risk their own money, which incentivizes accuracy. The oracle ensures honest resolution, and settlement locks in the final truth. This structure has roots in early experiments like the Iowa Electronic Markets and the Hollywood Stock Exchange, which demonstrated that crowds could forecast elections and box-office returns better than expert panels.
How market prices map to real-world probabilities
A contract trading at 65 cents suggests a 65% chance the event will happen. If you think the true probability is higher, you buy. If you think it’s lower, you sell. This process pushes the price toward the consensus forecast. Research on the wisdom of crowds shows that aggregated beliefs often beat individual experts, especially when participants have diverse information and financial skin in the game.
Prediction markets differ from polls in key ways. Polls ask people what they think. Markets ask people to put money where their mouth is. That financial commitment filters out noise and rewards accuracy. Studies comparing prediction markets vs polls consistently find that market prices track eventual outcomes more closely, particularly in volatile or uncertain environments.
The order book vs AMM design choice
Markets use two main mechanisms to match buyers and sellers. A central limit order book (CLOB) lists all bids and asks. You place an order at your desired price, and the exchange matches it with a counterparty. This design offers tight spreads and transparent pricing. Kalshi runs on a CLOB model, which appeals to traders who want control over execution.
Reading a Polymarket order book
Polymarket displays a ladder of buy and sell orders. The top bid shows the highest price someone will pay for a Yes share. The lowest ask shows the cheapest price someone will sell. The difference is the spread. Narrow spreads mean high liquidity. You can trade quickly without moving the price much. Wide spreads signal thin markets where large orders shift prices.