Direct Answer

Slippage is the difference between the price you expected and the price your order actually fills at. You click buy on EUR/USD at 1.0850, but in the half-second before execution the market jumps and you fill at 1.0853, three pips worse. It happens because prices move continuously while your order travels to the broker's server, and in fast markets the quote can change mid-flight. Slippage can be negative, costing you money, or positive, filling you at a better price than expected. Market orders and stop-loss orders suffer most because they accept whatever price is available.

When Slippage Strikes the Hardest

Slippage spikes when liquidity vanishes or volatility explodes. Major news releases like US non-farm payrolls, inflation data and central bank decisions can move prices dozens of pips in seconds, far beyond your expected fill. The daily market open and the rollover hour are thin, so even small orders can slip. Exotic pairs like USD/ZAR slip more than EUR/USD because fewer participants quote them. Weekend gaps are the extreme case: your stop loss set on Friday can fill far away on Sunday's open, since no trading happened in between to honor your price.

How Slippage Affects Stops and Pending Orders

Stop-loss orders become market orders once triggered, so they slip exactly when you can least afford it, during sharp moves. A stop placed ten pips away can easily fill fifteen pips away in a news spike, enlarging your loss beyond plan. Pending orders like buy stops face the same risk. Limit orders are the exception: a buy limit fills at your price or better, never worse, but it may not fill at all in a fast market. Some brokers offer guaranteed stop losses for a premium, and most platforms let you set maximum deviation so orders are rejected rather than filled far off. (Master order types here: stop loss and take profit orders.)

Practical Ways to Reduce Slippage

You cannot eliminate slippage, but you can shrink it. Trade liquid pairs like EUR/USD and GBP/USD during the London and New York sessions, when deep liquidity absorbs orders smoothly. Avoid placing market orders seconds before major news; either wait for the release or use limit orders with realistic prices. Choose a broker with fast execution and check independent reviews for slippage complaints. A VPS near your broker's server cuts transmission delay for automated strategies. Finally, size positions so that even a slipped stop loss stays within your risk tolerance, because some slippage on every active account is inevitable.

Frequently Asked Questions

Is slippage always bad for traders? No. Positive slippage fills you at a better price than expected and happens in the same fast markets. Over many trades it partly offsets the negative kind. Can my broker fake slippage to cheat me? Dishonest brokers can, through asymmetric slippage that only works against you. Stick to well-regulated brokers and compare your fills against independent price feeds if you suspect foul play. Do limit orders experience slippage? Never negative slippage. A buy limit fills at your specified price or better, but in a fast-moving market it may simply never fill, leaving you out of the trade.