Slippage
Slippage is the difference between the price a strategy assumes and the price it actually receives, and it is one of the main reasons live results trail backtests.
How it works
It comes from spread, latency between signal and fill, and the depth available at the moment of execution. Backtests commonly assume a fill at the signal bar's close or the next bar's open with no adjustment. On micro futures during liquid hours slippage is small but not zero; around scheduled releases and at the session open it widens sharply, which is why event windows distort a strategy's statistics disproportionately.
Why it matters on a funded account
Modelling it costs one line in a backtest and changes the profit factor materially on high-frequency strategies. Omitting it is the most common reason a strategy looks better in history than in an evaluation.
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Part of the Puravida Edge prop trading glossary. Firm-specific figures verified September 2026; rules change frequently — confirm on the firm's site.