Positive vs. Negative Slippage in High-Impact Hours
Slippage is the difference between the expected price of an order and the actual price at which the order is filled. Retail traders often assume slippage is inherently malicious, but under genuine ECN and STP execution environments, slippage is symmetric and market-driven.
- Negative Slippage: Occurs when your buy order fills at a higher price or sell order fills at a lower price than requested. This happens when available depth at your desired price is exhausted before your trade reaches the front of the queue.
- Positive Slippage: Occurs when sudden price movement works in your favor, filling a buy order lower or a sell order higher than anticipated. Legitimate ECN bridges pass this benefit directly to your account balance.
'During high-impact news releases, top-of-book depth on major currency pairs can drop from 50 million units to under 2 million within 300 milliseconds.'
When testing strategies from our YouTube strategy backtest code lab, remember that synthetic backtests rarely model order book depletion accurately. Factoring in at least 1.5 to 2.5 pips of dynamic execution drag during major economic releases is necessary to ensure realistic performance projections.