The Mechanics
A 'Yes' contract on an event trades at, say, 34¢ — implying the market judges a 34% chance. If the event happens, the contract settles at $1.00 (a 66¢ profit); if not, at zero. You can sell any time before resolution, so you're not locked in: buy at 34¢, sell at 60¢ after news moves the market, and the outcome itself never needs to arrive.
Why Prices Beat Pundits
Markets aggregate information ruthlessly: anyone holding better information profits by trading it in, moving the price toward truth. Decades of research — from Iowa Electronic Markets onward — show event markets matching or beating polls and expert forecasts across politics, economics, and sports. Not because traders are geniuses, but because being wrong costs money and being right pays.
The 2026 Landscape
Polymarket (on-chain, USDC, global) is the liquidity leader; Kalshi (CFTC-regulated) is the US-legal exchange with bank rails; PredictIt survives in its academic niche; Manifold offers play-money markets for learning. Regulation has warmed dramatically — event contracts on economics, weather and elections now trade under US federal oversight, something unthinkable a decade ago.