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Prediction-market glossary: 30 terms every Kalshi trader should know

A focused glossary of the language used on Kalshi, Polymarket, and the broader prediction-market ecosystem.

Last updated June 18, 2026

Core mechanics

  • Event contract — a binary YES/NO claim on a real-world outcome, paying $1 if true and $0 if false.
  • DCM — Designated Contract Market, a CFTC-regulated exchange. Kalshi is one.
  • CLOB — Central Limit Order Book, the matching engine pairing bids and offers.
  • AMM — Automated Market Maker, the formula-based alternative to a CLOB.
  • Resolution source — the predetermined authority that decides whether a contract resolves YES or NO.

Order types

  • Limit order — buy/sell at a specific price or better.
  • Market order — fill immediately against the current book.
  • Fill-or-kill — execute fully and instantly, or cancel.
  • Resting order — a limit order sitting on the book awaiting a taker.

Risk and pricing

  • Implied probability — the price as a percentage chance the event happens.
  • Spread — the gap between best bid and best ask.
  • Slippage — the gap between expected fill price and actual fill price.
  • Liquidity — how much notional you can trade without moving the price.
  • Mark-to-market — your unrealized P&L if you closed at the current mid.

Regulatory

  • CFTC — Commodity Futures Trading Commission, US federal regulator for futures and event contracts.
  • KYC — Know Your Customer, the identity verification required before trading.
  • 1099-B — IRS form Kalshi issues annually summarizing your trading activity.
  • Section 1256 — IRS tax treatment for certain regulated futures-style contracts.

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