Order book
Last reviewed 2026-08-07
Order book — definition
The list of all resting limit orders on both sides of a market, organized by price.
Reading the order book tells you the true cost of a trade: deep on one side means easy fills, thin means slippage.
Kalshi and Polymarket both expose full order books in their UIs.
Learn more: How prediction markets work
See also
Frequently asked questions
What does order book mean in prediction markets?
The list of all resting limit orders on both sides of a market, organized by price.
How does order book work in practice?
Reading the order book tells you the true cost of a trade: deep on one side means easy fills, thin means slippage.
Sources & further reading
- CFTC — Event contracts explainedU.S. Commodity Futures Trading Commission
- Kalshi — how prices and settlement workKalshi
- UMA Optimistic Oracle documentationUMA Protocol
Last reviewed 2026-08-07 · CollegePredictionMarkets.com