What Is the Difference between Positive and Negative Slippage in a Trade?

Negative slippage occurs when a trade executes at a worse price than the quoted price, which is the common result of front-running or high market volatility. Positive slippage occurs when a trade executes at a better price than the quoted price.

This can happen if the market moves favorably for the trader between order submission and execution, or if a large pending order is filled at a better-than-expected price. Traders generally aim for zero or positive slippage.