Slippage

Slippage is the pip-difference between the price a trader expects an order to be filled at and the price it is actually filled at. Slippage tends to occur when liquidity is low or in volatile markets, particularly in the run-up to important economic data releases. Slippage also affects stop orders as these are executed as market orders which are automatically filled at the next best price rather than re-quoting another price to the trader.