What is Slippage?

The difference between the price you requested and the price you actually got — small in quiet markets, brutal around news.

Slippage is the difference between the price you requested and the price your order actually filled at. Click buy at 1.0850 and get filled at 1.0853, and you took three pips of negative slippage. It happens because prices move in the milliseconds between your click and the broker's execution, and because there may not be enough liquidity at your exact price to absorb your order. Slippage can also be positive — fills better than requested — though traders remember the negative kind.

Slippage concentrates exactly where traders least want it: around high-impact news, at market opens after weekends, and in thin sessions when liquidity is shallow. It affects stop losses too — a stop is a market order once triggered, so in a fast move it can fill noticeably beyond its level, which is why guaranteed risk only truly exists with brokers offering guaranteed stops. Practical defences: avoid entering seconds before red-folder news, trade liquid sessions, and treat expected slippage as part of the cost of any strategy built on speed.