Prediction Market Glossary
A plain-English glossary of prediction-market terms — implied probability, open interest, volume, settlement, and more — for researchers, reporters, and analysts.
Bid, ask, and spreadBest buy price, best sell price, and the gap between them.
Binary (Yes/No) contractThe basic unit: pays $1 if a specific outcome happens, $0 if not.
CFTC-regulated exchangeA prediction market authorized and overseen by the U.S. CFTC.
Implied probabilityThe probability of an outcome implied by its market price.
KalshiA CFTC-regulated U.S. prediction-market exchange.
Last priceThe price of the most recent trade, read as an implied probability.
LiquidityHow easily contracts can be traded without moving the price.
Market, event, and contractThe three levels TickerTracker uses to organize prediction-market data.
Multi-outcome marketA market with many possible outcomes where one wins.
Mutually exclusive marketA market where exactly one outcome wins; prices sum to about 100%.
Notional valueThe dollar value of trading or a position: contracts × price.
Open interestThe number of contracts currently held open — money at stake right now.
Order bookThe live list of outstanding buy and sell orders by price.
PolymarketA large blockchain-based prediction market on Polygon, priced in USDC.
Polymarket US (PMUS)A separate, CFTC-regulated U.S. exchange, distinct from global Polymarket.
Prediction marketA market where contract prices reflect the odds of a future event.
Settlement (resolution)Resolving a market once the event is decided; winners pay $1, losers $0.
Trading volumeThe total number of contracts traded over a period — a measure of activity.