Price Slippage

Price slippage is the difference between an expected or referenced trade price and the average price at which the order actually executes.

Slippage can be favorable or unfavorable and arises when prices change, displayed size is limited, or an order consumes several book levels. It is more likely during volatility, gaps, thin liquidity, and for orders large relative to available depth. Limit orders constrain execution price but may not fill, while market and triggered stop-market orders favor execution and accept uncertain price.

Slippage can materially increase losses when leveraged positions are closed in fast or illiquid markets.