Prediction Market 101: How Event Contracts Work

Prediction Market 101 आपको सरल, व्यावहारिक अवलोकन देता है कि Polymarket जैसे मार्केट्स वास्तविक-दुनिया के प्रश्नों को ट्रेडेबल कॉन्ट्रैक्ट्स में कैसे बदलते हैं। आप सीखेंगे कि एक कॉन्ट्रैक्ट क्या दर्शाता है, कीमतें संभाव्यता से कैसे संबंधित हैं, खरीदने और बेचने की बुनियादी यांत्रिकी, और वे जोखिम जो हर शुरुआती को पोजिशन लेने से पहले जानने चाहिए।

Key takeaways

• A prediction market contract is a tradable token that pays $1.00 if its outcome resolves YES and $0.00 otherwise. Prices act like probabilities.
• Binary markets have complementary YES/NO outcomes; multi-outcome markets split probability across several mutually exclusive outcomes. The fair sum of outcome prices equals $1.00.
• Trading on Polymarket uses a Central Limit Order Book (CLOB) and pUSD (Polymarket’s wrapped USDC). Gas is sponsored by the Polymarket Relayer.
• Common risks: oracle disputes during resolution, partial fills and slippage, fee and timing changes, and smart-contract risk. Never assume a spread is unconditional profit without listing these risks.

What a prediction market contract is

A contract (sometimes called an event contract or outcome token) represents a single possible result of a real-world question. For binary markets the outcomes are YES and NO. Each share of a winning outcome redeems for $1.00 at settlement; losing outcomes become worthless.

Think of a contract price of $0.72 for YES as the market saying there’s roughly a 72% chance the event will happen. That interpretation is intuitive but not literal — prices reflect supply and demand, fees, and traders’ time preferences.

Binary vs multi-outcome markets

• Binary markets have exactly two outcomes (YES and NO). At fair value, YES price + NO price = $1.00.
• Multi-outcome markets split probability across N exclusive outcomes. The fair sum of their prices equals $1.00.

This accounting identity is the basis for many arbitrage strategies: if the sum of best asks across all outcomes is below $1.00, you can buy a complete set and lock the difference (see our guides on intra-market arbitrage). But remember: the arithmetic edge is subject to execution risk and settlement risk.

How prices are created

Prices come from traders posting limit orders (bids and asks) and market orders on the CLOB. The best bid is the highest price someone will buy at; the best ask is the lowest price someone will sell at. The midpoint is the average of those two.

On Polymarket the CLOB enforces tick sizes ($0.01 usually, tightening to $0.001 near extremes) and records order-book depth. Maker fees are zero; taker fees vary by category.

From limit orders to probabilities

When you place a limit order you’re offering liquidity at a specific price. If your order executes, you’re either buying a contract that may settle at $1.00, or selling a contract you hold. Market sentiment, new information, and liquidity shape price movement.

Mechanics unique to Polymarket

• Settlement asset is pUSD (Polymarket’s wrapped USDC). You need pUSD to trade.
• Polymarket uses Gnosis’s Conditional Token Framework (CTF) under the hood, so each outcome is an ERC-1155 token you can split, merge, and redeem after resolution.
• Gas is sponsored: the Polymarket Relayer pays gas, so common actions (wallet deployment, approvals, order placement) are gas-free for users.

How resolution works

Polymarket relies on the UMA optimistic oracle for final reporting. When an event resolves, the oracle posts a result and there’s a dispute window. If disputed, settlement pauses until UMA rules. This creates a non-zero resolution risk — even after a market appears finished, funds can be locked while disputes are resolved.

Common workflows for new users

• Fund your wallet with pUSD. Polymarket accepts pUSD for trading; see our related guide on funding for step-by-step instructions.
• Connect a wallet (MetaMask, a Proxy, or a Gnosis Safe). Polymarket supports several wallet connectors and deploys a Proxy automatically if needed.
• Place a limit order if you want control over price, or a market/FAK order for immediate execution. FAK (Fill-And-Kill) orders either fill instantly or cancel the remainder.

What traders pay and what to watch

Fees vary by category; taker fees are variable (0%–1.8% range) while maker fees are zero. The “Geopolitics” category is fee-free. Always check the fee for a market before assuming an arbitrage or quick flip will be profitable.

Practical risks — the checklist every beginner should hold in mind

• Resolution risk: UMA disputes can delay or change the outcome.
• Execution risk: partial fills and slippage can erode expected profit.
• Fee risk: taker fees and unexpected fee changes reduce returns.
• Settlement timing: redeemed funds may take time to appear during disputes.
• Smart-contract risk: while Polymarket uses audited frameworks, on-chain risks remain.
• Regulatory/geographic restrictions: Polymarket blocks certain jurisdictions; do not attempt VPN bypass (it violates Polymarket’s Terms of Service).

A short history note

Between April 2024 and April 2025 arbitrageurs extracted roughly $40 million from Polymarket markets. That figure illustrates how quickly markets can correct inefficiencies, especially on liquid questions.

How this affects your trading

Start small and practice reading order books. For beginners, focus on understanding how prices change after news and how the order book depth affects your fills. If you plan to attempt arithmetic arbitrage, practise on paper first and always list the risks for every presumed 'edge'. Use limit orders to control entry price and be conservative when markets approach resolution because tick sizes and liquidity can change rapidly.

Further reading

• If you want the technical view of order mechanics, read our guide on Polymarket CLOB (/guides/polymarket-clob-explained).
• For arbitrage techniques, see the complete arbitrage guide and the intra-market binary walkthrough in the related links below.

Closing summary

Prediction market 101 explains that event contracts are conditional tokens that pay $1.00 on a winning outcome and trade on price as a probability signal. Understanding order-book mechanics, the CTF settlement flow, and the risks around resolution are the foundations you need before trading on Polymarket.

Frequently asked questions

What does a $0.40 price mean in a prediction market?

A price of $0.40 indicates the market values that outcome at roughly a 40% chance of occurring. Prices reflect aggregated trader beliefs plus fees and liquidity; they are not guarantees.

How do I settle a winning contract on Polymarket?

After the market resolves via the UMA oracle, winning outcome tokens can be redeemed for $1.00 each using the Conditional Token Framework's redeem operation. If the resolution is disputed, settlement pauses until UMA resolves the dispute.

Are prediction markets legal everywhere?

Polymarket enforces geographic restrictions and blocks certain countries and regions from placing new orders. The United States is blocked from polymarket.com for new orders; a separate regulated pathway exists. Do not use VPNs to bypass restrictions.

What is FAK and when should I use it?

FAK means Fill-And-Kill — a market order that executes immediately for any available liquidity and cancels the remainder. Use FAK when you prioritize speed over price certainty, but be aware of slippage and taker fees.

How do fees affect small trades?

Taker fees can be a meaningful percentage of a small trade's expected profit. Maker fees are zero, so posting limit orders can be cheaper, but you may not get filled. Always check the market’s fee category before trading.