When you’re trading Forex, sometimes you’ll notice a slight difference between the price you expect and the execution price (the price when the FX trade is completed). When this happens, it’s known as slippage. It’s a common thing to experience as a Forex trader and it can work either positively or negatively.
The main reasons for slippage are Forex market volatility and execution speeds.
When a market experiences high volatility it generally means there’s low liquidity and market prices fluctuate very quickly. Where this affects Forex traders is when there’s not enough FX liquidity to fill an order at the requested price. When this happens, the liquidity provider will complete the trade at the next best price.
Another cause for slippage is Execution Speed. This is how fast your Electronic Communication Network (ECN) can complete your trade at the price you want it to. With market prices changing in fractions of a second, having faster execution times can make a difference, especially on large trades.