When big news breaks, markets react instantly. Shares gap lower, currencies jump and futures swing sharply. But the first move is often not the final one. Prices frequently run further than the news justifies, then partly reverse once traders have had time to think. Understanding why this happens can help you avoid buying at the top of a spike or selling at the bottom of a plunge.
Liquidity is often thin
Many major events happen outside normal trading hours or at moments when few people are ready to trade. Election results arrive overnight, company results come out after the close and central bank surprises can hit during quiet periods. With fewer buyers and sellers, a wave of orders in one direction can push prices much further than it would in a busy market.
Stop-losses and forced selling
Lots of traders use stop-loss orders, which automatically sell if the price falls to a certain level. When a sharp move triggers those stops, the extra selling pushes prices lower still, which can trigger the next set of stops. Leveraged traders may also face margin calls, forcing them to sell regardless of their view. This chain reaction can create a move that has more to do with market mechanics than with the news itself.
Positioning matters
If lots of investors are holding the same trade, they can all rush for the exit at once when news challenges it. This is what traders mean by a crowded trade. The more crowded the position, the sharper the first reaction tends to be. After the 2026 US midterms, for example, technology shares were already heavily owned and nervous, which helps explain why futures fell so fast. Our Morning Market Brief looked at that reaction.
Headlines before details
The first reaction is usually based on a headline. The details come later. A surprise election result, a big earnings miss or an unexpected rate move all need to be digested. Once analysts work through what it actually means for profits, interest rates and growth, the market often decides the first move went too far. Sometimes, of course, it decides it did not go far enough.
Not every move reverses
It is important not to turn this into a rule. Some first moves are the start of a lasting trend, particularly when news genuinely changes the outlook. Assuming every sharp drop will bounce is a common and expensive mistake, which we cover in our guide to buying every dip in a falling market. The skill is in judging whether the reaction matches the real change in fundamentals.
How traders approach it
Experienced traders often wait for the first wave to pass before acting. They watch how prices behave once normal liquidity returns, for example after the first half hour of the cash session. They compare the size of the move with the likely real impact and keep positions small until the picture is clearer.
The beginner’s takeaway
The first reaction to big news is driven by thin liquidity, stop-losses, crowded positions and headlines rather than full analysis. That is why it often overshoots. Patience and a clear view of what has really changed are your best protection.
Staying calm when markets are not is a skill that can be learned. To see how your own approach stacks up, take the free Samuel & Co Trading Trader Assessment.
