Slippage is the difference between the price you intended and the price at which your order actually fills. You click to buy GBP/USD at a level you see on the screen, or your stop is sitting at a round number, and the fill prints a few points worse. That gap is slippage. It is not always a broker “stealing” from you. Often it is the market moving faster than a simple order can meet liquidity at your exact price.
Beginners notice it most on the trades that already hurt. That is when they start searching for villains instead of mechanics.
Why Slippage Happens
Markets are continuous auctions. At any moment there is a finite amount of size available at each price. If your order is larger than what sits at your preferred level, or if price has already jumped, the next available liquidity is worse for you. Fast markets—UK CPI, labour data, unexpected headlines into the London session—thin out the book. Spreads widen. Stops cluster. Fills gap.
On the FTSE 100 around the cash open or a major UK print, index CFDs and futures-linked prices can gap through levels that looked solid on a quiet chart. Your stop was not ignored. There was no trade at that price when your order hit the queue.
Thin liquidity in off-hours can produce the same effect on sterling even without a headline, especially if size is large relative to the visible book.
Positive and Negative Slippage
Negative slippage is the familiar kind: buy fills higher, sell fills lower, stop exits worse than the stop price. Positive slippage can happen too, especially with limit orders that rest and catch a better print. Beginners rarely screenshot the good fills. They remember the bad ones after a stop is blown through.
Market orders prioritise speed of fill over price. Limit orders prioritise price and may not fill at all. Neither removes uncertainty; they allocate it differently. A plan should say which order type belongs to entries and which belongs to exits for your style.
Stops, Gaps, and News
A stop-loss is an instruction to exit at the market once a trigger price trades. In a gap, the trigger can be leapt over. Overnight on FX, or into a Monday open on indices, that matters. Trading GBP through a thin Asian patch with a stop that assumes London liquidity is a common beginner mistake.
If your plan allows holding into scheduled news, expect wider spreads and worse stop fills as part of the cost of that choice—not as a surprise. Many UK beginners simply stand aside for a few minutes around high-impact releases. That is a plan decision, not fear.
A free traders assessment is one way to see whether your largest losses sit on news windows where slippage and size combined, rather than on “normal” London hours.
How Beginners Should Think About Cost
Treat average slippage as a friction cost, like spread. Measure it over many trades in pounds, not by one angry example. If you scalp tiny targets, slippage can erase the edge. If you swing with wider stops and larger R targets, the same absolute slip matters less as a percentage of the trade.
Reduce size into events. Avoid market orders when a limit will do. Do not place stops exactly where every textbook and every other retail trader parks them if you can define invalidation a little beyond the obvious round number—without pretending that eliminates gap risk.
Keep a simple note in the journal: intended price, fill price, session, news or quiet. After twenty trades you will know whether your platform and hours are acceptable, or whether you are fighting conditions you should not trade.
Before you change brokers over one fill, a free traders assessment can help separate execution friction from oversized risk as the main account problem.
Conclusion
Slippage is the fill you get when the market will not meet you at the price you wanted. It rises with speed, size, and thin books—conditions UK traders meet around sterling and FTSE news. You cannot legislate it away. You can size for it, schedule around it, and stop treating every worse fill as a mystery.
Samuel and Co Trading frames slippage as market structure, not folklore. Know when your session is fragile, keep size modest into events, and judge brokers and platforms over a sample of fills—not one screenshot.
