> For the complete documentation index, see [llms.txt](https://docs.trade.xyz/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.trade.xyz/events/event-contract-mechanics.md). # Contract Mechanics How Events outcome tokens trade and settle on Hyperliquid HIP-4. Events are fully collateralized Hyperliquid outcome markets. They settle within a fixed range and do not use leverage, funding, liquidations, or auto-deleveraging. ## Two sides with one economic book A binary market has two outcome tokens, commonly shown as Yes and No. HyperCore combines the two sides into one economic order book: buying Yes at price `p` is equivalent to selling No at `1 - p`. This relationship allows liquidity posted through either side to participate in the same market. Advanced users can use Hyperliquid’s [split](https://hyperliquid.gitbook.io/hyperliquid-docs/for-developers/api/exchange-endpoint#split-outcome) and [merge](https://hyperliquid.gitbook.io/hyperliquid-docs/for-developers/api/exchange-endpoint#merge-outcome) actions to convert between collateral and outcome balances. Historical API responses may show the primary and dual orders separately even when the interface presents a single combined book. ## Prices and probabilities For binary markets settling between 0 and 1, prices are often interpreted as market-implied probabilities. That interpretation is approximate. Fees, liquidity, bid-ask spreads, position constraints, and other market conditions can cause price to differ from a participant’s estimate of the event’s likelihood. Trade\[XYZ] does not represent a market price as a guarantee or statement of fact and does not endorse any prediction. ## Settlement At settlement, HyperCore converts the two outcome balances according to the submitted `settleFraction`. In a binary result: * `settleFraction = 1` pays one quote token per Yes token and zero per No token. * `settleFraction = 0` pays zero per Yes token and one quote token per No token. Some HIP-4 contracts may use a settlement value between 0 and 1 if their market terms allow it. Please refer to the applicable market terms and [Resolution](/events/resolution.md) methodology. ## Questions with multiple outcomes HIP-4 enables grouping related outcomes into a question where one outcome settles to Yes and the others settle to No. Each outcome has its own order book, while HyperCore’s negate and merge operations link the balances economically. See Hyperliquid’s [HIP-4 outcome-market documentation](https://hyperliquid.gitbook.io/hyperliquid-docs/hyperliquid-improvement-proposals-hips/hip-4-outcome-markets) and [exchange API](https://hyperliquid.gitbook.io/hyperliquid-docs/for-developers/api/exchange-endpoint#split-outcome) for protocol-level details. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.trade.xyz/events/event-contract-mechanics.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.