What is a prediction market?

A market where contracts pay out on a real-world outcome: $1 if it happens, $0 if it does not. The price of a contract, somewhere between 0 and 100 cents, is the market's live estimate of how likely that outcome is.

How do I read a price like 54%?

As the probability the market currently gives the outcome. Traders are paying 54 cents for a contract that pays $1 if it happens. Someone who believes the true chance is higher buys Yes; someone who believes it is lower buys No.

Which platforms do the guides cover?

Polymarket and Kalshi. The mechanics are the same on both; the guides point out where the two differ, from settlement rules and fees to which events each one lists. The scanner shows the two prices side by side.

Do I need an account to read the guides or use the scanner?

No. The guides, the glossary and the market scanner are open to everyone. A free account adds followed events, a weekly digest and a practice-trading desk.

How does practice trading work?

The practice desk uses live market prices and simulated funds, so a strategy can be tested against real markets without money at stake. Nothing is bought or sold on any platform.

What is the difference between a guide and an event page?

A guide explains how something works and stays useful for months: how contracts settle, how to read an order book, how to hedge a business risk. An event page follows one live topic and its markets as they move. Guides link to the event pages where the mechanics show up in practice.

Prediction market analysis.

Market context, guides and case studies to help you understand prediction markets.

From the experts.

G.R.C.

PhD, 35+ years in catastrophe risk

Explore all guides.

Question marks spray-painted in teal on the trunks of pine trees in a forest.

FundamentalsWho actually makes money on prediction marketsMost prediction market traders lose money, and a small share collects most of the profit. What the data shows about who wins, why most lose, and what helps.

A small figure standing at the entrance to a large gray maze, seen from above.

FundamentalsWhy you should be skeptical of prediction market wins on social mediaViral videos showed creators winning big on prediction markets. The trades were never placed. How the wins were faked, what they would really have made, and who paid.

A hand holding two black cards with the words Buy and Sell cut out of them.

FundamentalsIs paper trading a good test of prediction market skill?What paper trading on live prediction market prices tests well, why a high win rate can mislead, and what it cannot show about trading with real money.

A white sign reading Closed hanging from the wooden handle of a black wire-glass door.

FundamentalsWhat happens to a position when a prediction market closes earlyWhy a market stops trading before its listed date, where Kalshi and Polymarket say so in the rules, and what happens to a position and open orders when it does.

A white card with the handwritten word Resolutions nailed to a weathered wooden fence rail with peeling white paint.

FundamentalsWho decides how a prediction market resolvesWhere the resolution source is written, how Kalshi's staff and Outcome Review Committee and Polymarket's UMA oracle decide the outcome, and whether a result can be reversed.

A long row of stainless steel laundromat dryers with round glass doors, fading out of focus.

FundamentalsUnderstanding wash trading in prediction marketsWhat wash trading is, what the rules say, how much volume the studies attribute to it, and what fake volume means for anyone reading a prediction market.

A gold Bitcoin symbol on a dark rounded cube beside a small gold coin and a rising arrow.

FundamentalsThe speculative mechanics of short-term crypto prediction marketsCoin-flip pricing, taker fees that peak at 50 cents, automated market makers on the other side, and volume figures that count payouts rather than cash.

Cracked, dried-out earth seen from above.

Climate & WeatherDrought basics: the types, the D0 to D4 scale, and the worst US droughtsThe types of drought, the D0 to D4 severity scale, and the worst droughts in US history.

A tornado funnel descending from a dark storm cloud over green farmland.

Climate & WeatherSevere storm basics: tornadoes, hail, damaging winds, and when they strikeTornado ratings, how severe thunderstorms form, the seasonal pattern, and the records.

Black and white photograph of buildings burning on Market Street after the 1906 San Francisco earthquake.

Climate & WeatherEarthquake basics: faults, magnitude, and where US risk is highestFaults, magnitude, the largest US earthquakes, and California's 30-year odds.

A white pickup truck driving through deep floodwater, throwing up a wake of spray.

Climate & WeatherHurricane basics: how they form, how they're rated, and what drives themHow hurricanes form, how they are rated, when the seasons run, and what drives their strength.

A white question mark painted on a dark paved sidewalk, split by two grout lines.

FundamentalsWho is on the other side of a prediction market tradeMarket makers, the exchange's own affiliate, bots, insiders, hedgers and wash traders: who fills an order on Kalshi and Polymarket, and what each one wants.

Prediction market glossary.

View the full glossary

Implied ProbabilityPricing & Probability: The market's estimated likelihood, derived from the contract price.
SettlementSettlement & Resolution: When a contract resolves and payouts are distributed.
SpreadPricing & Probability: The difference between the best buy and sell price.
LiquidityPlatforms & Regulation: How easily you can trade at the price you want.
Order BookTrading Mechanics: The list of pending buy and sell orders at various prices.
Event ContractPlatforms & Regulation: A prediction market contract tied to a real-world outcome.
Binary ContractPricing & Probability: A contract that resolves to $1 (Yes) or $0 (No).
Resolution SourceSettlement & Resolution: The data source that determines a contract's outcome.

Prediction market analysis.

From the experts.

Earthquakes

Hurricanes

Severe storms

Explore all guides.

Prediction market glossary.

Prediction market FAQ.

Join the community.