You go to bed with a share at £50 and wake up to find it opening at £44. Nothing traded in between. That jump is a gap, and results days are where the biggest ones happen. Understanding why shares gap after results, and how to manage the risk, can save beginners from some painful surprises.
What a results-day gap is
A gap is when a share opens at a price noticeably different from where it last closed, leaving an empty space on the chart. Results gaps happen because most large companies publish results outside normal trading hours, either after the close or before the open. The news is absorbed overnight or in after-hours trading, so when the regular session begins, the price jumps straight to a new level.
Why gaps happen
Results often change investors’ view of a company’s value all at once. A strong beat, a cut to guidance, a big change in spending plans or a surprise in one segment can shift what investors are willing to pay. Because the news arrives when the main market is closed, there is no gradual adjustment. The new price shows up in one move.
The size of the gap often relates to how surprising the news was compared with expectations. The options market gives a guide to the likely size in advance through the earnings implied move.
Why gaps are risky
The main risk is that a stop loss does not protect you. If your stop is at £48 and the shares open at £44, the stop is triggered at the open and filled near £44, not £48. Your loss can be several times larger than planned. This is why holding shares through results is a different risk from holding them on a normal day.
What happens after the gap
Some gaps get filled, meaning the price moves back towards the previous close as the initial reaction fades. Others keep going in the direction of the gap for days or weeks, especially when results change the long-term story. There is no reliable rule. Traders often wait to see how the shares behave in the first 30 to 60 minutes, and whether early buyers or sellers are in control, before deciding.
A simple example
A company reports after the US close. Revenue narrowly misses and spending plans rise sharply. In after-hours trading, the shares fall 8 per cent. At the next morning’s open, they start around that level. One trader who held through the results has lost 8 per cent overnight, despite having a stop at 3 per cent. Another trader who sized their position for an 8 to 10 per cent gap is disappointed but within their risk limits.
How to manage gap risk
Know the results date for anything you hold. Decide in advance whether to hold through it, reduce your position or step aside. If you hold, size the position so a gap of twice the implied move would still be an acceptable loss. And avoid chasing the opening move; let the market settle first.
Common mistakes
The most common mistake is relying on a stop loss to protect against results risk. Another is assuming every gap will be filled. A third is forgetting that UK companies often report at 7am, so London shares can gap at 8am just as US shares gap at the New York open.
The bottom line
Results-day gaps happen because news arrives when the market is closed. They can make losses much larger than planned, so the key is preparing before the release rather than reacting afterwards. If you want to test how you manage event risk, the free Samuel & Co Trading Trader Assessment is a sensible next step.
