Polymarket is a prediction-market platform where prices move with traders’ views of real-world events. This guide explains what a share represents, how order-book prices become implied probabilities, what actually happens when you buy or sell, how resolution works, and what to verify before risking money.
What is Polymarket?
Polymarket is a non-custodial prediction-market platform built around questions with verifiable outcomes. A market might ask whether a candidate will win an election, whether a cryptocurrency will cross a price threshold, or whether a team will win a tournament. Traders buy and sell shares in the possible outcomes instead of placing a wager against fixed odds set by a house.
Its current documentation describes a peer-to-peer central limit order book, smart-wallet infrastructure, and onchain settlement. Availability is not universal: access, identity requirements, and legal treatment can differ by jurisdiction and can change. A platform description is therefore not an eligibility statement; check the current terms that apply to you.
What does a Polymarket share represent?
A binary market has YES and NO shares. Polymarket’s documentation says each share trades between $0 and $1 and every fully backed YES/NO pair is created against $1 of pUSD, its current collateral unit. When the market resolves, each winning share can be redeemed for $1 pUSD and each losing share is worth $0.
Suppose you buy ten YES shares at an average price of $0.62. Your purchase value is $6.20 before applicable fees. If the market later resolves YES and you still hold the shares, their gross redemption value is $10. If it resolves NO, their redemption value is $0. If you sell before resolution, your result depends on the price and liquidity available when your sell order executes.
| Outcome | Gross value of 10 YES shares | What determines the result |
|---|---|---|
| Market resolves YES | $10 | Winning shares redeem for $1 each |
| Market resolves NO | $0 | Losing shares become worthless |
| You sell before resolution | Execution price × shares | Bid, depth, fees, and fill quality |
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How Polymarket prices become probabilities
A share price is usually interpreted as an implied probability. A YES share around $0.65 is commonly described as the market assigning about a 65% chance to YES. That shorthand is useful, but the number is not a scientific forecast and it is not a promise. It is a price produced by the orders currently available from traders.
The distinction becomes clearer when you separate the best bid from the best ask. If the highest buyer will pay $0.34 and the lowest seller will accept $0.40, the midpoint is $0.37. A buyer generally crosses to the $0.40 ask; a seller generally crosses to the $0.34 bid. Polymarket’s documentation says its displayed price normally uses the midpoint, but if the spread is wider than $0.10 it displays the last traded price instead. Neither figure automatically equals your executable price.
How trading works on Polymarket
Polymarket matches users through a central limit order book. Bids are open buy orders and asks are open sell orders. When compatible orders meet, they trade. This structure enables price discovery, but it also means the quality of an entry or exit depends on other participants’ orders. Thin markets can have wide spreads, limited depth, and partial fills.
A market order prioritizes immediate execution against available liquidity. A limit order specifies the worst price you are willing to accept and may remain unfilled. The right choice depends on urgency, spread, depth, and how much price uncertainty you can tolerate. Clicking a side labelled YES or NO is only the beginning; the order type and final review determine what you are asking the venue to execute.
A real Hunch interface example
Hunch aggregates prediction-market discovery and trading context. In a product check on 15 August 2026, the Hunch page for the 2028 Democratic presidential nominee event showed a Polymarket market for Alexandria Ocasio-Cortez with an executable YES indication of 20.1¢ and NO indication of 80¢. Entering $10 on YES showed an estimated 49.7512 shares and a potential $49.75 payout before submitting the trade.
This timestamped example is not a recommendation and those numbers will change. It demonstrates why YES and NO indications need not add to exactly $1: the interface is showing tradable sides of an order book, not merely two complementary headline probabilities. Hunch labels share quantity as approximate and presents estimates before the user proceeds.
Does Polymarket charge fees?
Fees are market-dependent. Polymarket’s current documentation says makers are not charged trading fees and takers pay a protocol fee on certain market categories, with the amount varying by category and share price. It also says geopolitical and world-event markets are fee-free and that third parties may charge for deposit or withdrawal routes even when Polymarket itself does not.
Do not copy a fee percentage from an old guide into a new trade. Check the specific market’s current fee parameters and the final review shown by the interface you use. Your real return also depends on spread, slippage, funding costs, and any costs charged by intermediaries.
How Polymarket markets resolve
Every market has resolution rules that define the source, end conditions, and treatment of edge cases. The title is a summary; the rules decide the winner. Polymarket currently uses the UMA Optimistic Oracle process. An outcome is proposed with a bond, a challenge period allows disputes, and disputed cases can escalate through further proposal and UMA voting steps.
An undisputed result can settle quickly, while a disputed or ambiguous market can take longer. Polymarket’s documentation also describes rare 50/50 outcomes in which each side redeems for $0.50. The practical lesson is simple: being right about the news is not enough if your interpretation differs from the contract’s exact wording and designated source.
The risks beginners should understand
- Forecast risk: the event can resolve against your position and the full purchase value can be lost.
- Execution risk: spreads, shallow depth, partial fills, and price movement can make the actual trade worse than the displayed probability.
- Resolution risk: wording, sources, deadlines, clarifications, and disputes can produce a result different from an intuitive reading of the event.
- Operational risk: wallets, keys, smart contracts, networks, bridges, and third-party funding services can fail or be used incorrectly.
- Fee and cost risk: protocol fees, spread, slippage, and intermediary charges reduce returns.
- Access and legal risk: venue availability and applicable rules vary by user and jurisdiction and can change.
How to use Polymarket markets through Hunch
Hunch is designed as an aggregator rather than a single-venue newsroom. You can discover an event, inspect the specific market and venue, choose YES or NO, enter an amount, and review estimated shares, spend, payout, and available fee information before continuing. Where comparable markets exist on other venues, Hunch can also make the venue context easier to inspect.
For your first trade, start with the step-by-step Hunch guide. For the broader concepts behind every venue, read What Are Prediction Markets?.
Polymarket turns collective beliefs into tradable prices, but the large percentage on a market page is only the start of the analysis. The contract rules determine what wins, the order book determines what you can trade, and your sizing determines how much you can lose.