# Self-Trade Prevention **Current Behavior** Lighter imposes a self-trade prevention mechanism. Trades between the same account cancel the resting order (maker) instead of executing the respective trade. Without this mechanism, self-trades would result in no position change and fees being paid unnecessarily. **Upcoming Change** Default self-trade behavior on Lighter will change from reduce both to cancel maker: • Current default (reduce both): When a user's order crosses their own resting order, both orders are reduced by the overlap amount.\ • New default (cancel maker): The resting order is cancelled in full, and the incoming order continues filling against the rest of the book. This means that under the new default behavior, the taker order fills as intended against the rest of the book, instead of being silently reduced. The change only affects orders that don't explicitly specify a self-trade behavior. All four modes (cancel maker, cancel taker, cancel both, reduce both) will be allowed as explicit transaction attributes when placing the order. The above changes will be effective starting May 31st, 2026 at 8:00 AM ET (timestamp: 1780228800) --- # Agent Instructions: 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: ``` GET https://docs.lighter.xyz/trading/self-trade-prevention.md?ask= ``` The question should be specific, self-contained, and written in natural language. 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.