> ## Documentation Index
> Fetch the complete documentation index at: https://docs.openoracle.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Max profit

Every position has a maximum profit. When the matcher takes the other side, they lock margin for the life of the position, which is all the trader can win. The trader decides how much matcher margin to ask for with **Max ROE**, the maximum profit as a percentage of the trader's margin.

If the PnL overshoots the matcher's margin, the extra gain is not paid. The position does not close by itself when this happens, so it is up to the trader to close it.

## Example

A trader opens a \$1,000 long at 10x with \$100 of margin and Max ROE of 200%. The matcher locks \$200.

If the price rises 30%, the position is up \$300 on paper, but the trader can win at most \$200, before fees and funding.

## Auto

Max ROE is under Advanced Settings. On Auto, it is sized so that the margin your counterparty posts covers most price moves over the [maturity](https://docs.openoracle.org/punt/maturity.md).

A higher Max ROE asks the matcher to lock more margin, which can make the position harder to fill.


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