Market Structure & Hierarchy
| Term | Definition |
|---|---|
| Category | Broadest classification level organizing instruments by event type (e.g., Sports, Politics, Crypto, Culture). |
| Series | More specific classification within a category, such as a sports league or topic (e.g., NFL, NBA, US Presidential, Bitcoin). |
| Event | A specific occurrence with multiple possible outcomes. Each event consists of one or more instruments representing the complete set of tradable outcomes. |
| Product | The type of contract structure used to format instruments (e.g., Athletic Event Contract, Election Winner Contract, Total Score Contract). |
| Instrument | The tradable symbol representing a specific outcome for an event. Follows consistent naming conventions for easy identification. Also called a market. |
| Participant | The possible outcomes in an instrument. The long participant represents the “Yes” outcome; positions on the opposing outcome are achieved by selling (shorting) the long participant. |
| Market | Same as an instrument. A tradable outcome with defined resolution criteria and sources. |
| Contract | An instance of an instrument. You trade contracts in quantities (e.g., buying 100 contracts). Each contract settles at $1.00 if the outcome occurs and $0.00 if it does not. |
Trading Basics
| Term | Definition |
|---|---|
| Long position | Buying contracts of an instrument, trading on the outcome occurring. You pay the current price per contract and receive $1.00 per contract if the outcome happens. |
| Short position | Selling (shorting) contracts of an instrument, trading on the outcome not occurring. You receive the current price per contract but must cover potential losses if the outcome happens. |
| Order | A request to buy or sell contracts at a chosen price. |
| Order book | List of bids and asks showing available prices and size at each level. |
| Bid | Highest price buyers are willing to pay. |
| Ask | Lowest price sellers are willing to accept. |
| BBO (Best Bid and Offer) | The best bid and ask prices currently available in the order book - the tightest spread at the top of the book. |
| Spread | Gap between the bid and the ask. |
| Size | Number of contracts available to buy or sell at a given price. |
| Liquidity | How much size is available to trade at listed prices. |
Order Execution
| Term | Definition |
|---|---|
| Fill | When your order completes, fully or partially. |
| Partial fill | When only part of your order fills. |
| Execution price | The price at which your order fills. |
| Fill price | Average price you receive when your order fills across multiple levels. |
| Marketable limit order | An order that fills at the best available price shown on your screen. |
| Price impact | How much your fill price changes because of limited liquidity. |
| Slippage | Difference between expected and actual execution price. |
| Maker | Trader who adds liquidity by placing an order on the book. |
| Taker | Trader who removes liquidity by filling an existing order. |
Positions & Account
| Term | Definition |
|---|---|
| Open position | Contracts you currently hold. |
| Closed position | A position you no longer hold because you sold it or the market resolved. |
| Position value | Real-time dollar value of your open positions. |
| Cash balance | Funds in your account not tied to open positions. |
| Buying power | Cash available to open new positions after margin is applied. |
| Instant buying power | Part of your deposit that becomes available to trade immediately. |
| Margin | Funds locked to cover the maximum possible loss of a short position. Equal to $1.00 per contract shorted. |
| Max gain | The most you can earn on a position. |
| Max loss | The most you can lose on a position. |
Market Lifecycle
| Term | Definition |
|---|---|
| Clarification | Extra context added to explain how rules should be understood. |
| Resolution | When Polymarket determines the final outcome of a market using the sources listed in the rules. |
| Settlement | Final payout of $1.00 for winning contracts and $0.00 for losing contracts. |
Fees & Display
| Term | Definition |
|---|---|
| Fees | Trading or platform fees applied to executed orders. |
| Odds display | How prices are shown, such as price, percent chance, or American odds. |
| Open order | An order waiting on the book to be filled. |
| Order status | Whether an order is open, filled, or partially filled. |
| History | Section showing your past filled orders and closed positions. |