in your original post you mentioned nothing of a limit order.
limit orders do not by definition have price slippage.
Limit orders may actually have slippage depending on how your broker routes them, and their timing with market movements. Note: a limit order may only have slippage when the market is moving against them.... otherwise, they simply will not be filled, which can be an equally significant problem.
Slippage refers to the fact that one cannot trade a stock necessarily for what it most recently traded for.
This is do to the facts that in all markets a spread exists, market depth is finite, and that a small and varying amount of time passes between the time any order is issued and when it is filled.
This is especially obvious when a winning backtested strategy is executed in real time.
As for market orders, try and purchase 10 billion shares of a stock at once, and you will find out exactly what slippage is.
Quote from snugglepuppy666:
please read above.. i said LIMIT order.. would anyone please define how this relates to a lay person like me..