What is Slippage?
The difference between the price you expected to fill at and the price you actually filled at — usually negative during volatility.
Slippage is the difference between your expected fill price and the price actually executed. Positive slippage means you got a better price than expected; negative slippage means worse. For market orders during normal liquidity, slippage is usually within 0.5-2 pips. During news events or thin liquidity (Asian session start), slippage can spike to 10-50+ pips.
Slippage symmetry is the key quality metric. A broker with frequent negative slippage but rare positive slippage is treating you asymmetrically — sign of an unfavorable execution model. Tier-1 regulators (FCA, ASIC) require brokers to disclose slippage statistics in regulatory reports.
Limit orders avoid negative slippage entirely (they only fill at the limit price or better) but accept the risk of not filling. Stop orders and market orders are subject to slippage. For news traders, the only protection is a guaranteed stop-loss (some brokers offer it for a small premium).