Psychologie a chování
Investment Mistake of the Month: Selling in Panic During a Market Downturn
Key takeaways
- Panic selling means realising a loss that would have been erased over time through patient holding.
- The market has historically always recovered its losses after every major downturn — those who stayed the course did not get hurt.
- The worst days in the market and the best days in the market tend to cluster together — those who sold in panic miss both.
- The key is having a portfolio set up so that you do not need to touch the money during a downturn.
- Rules written in advance (an investment plan) save you from emotional decision-making in the heat of the moment.
Panic selling during a market downturn is the investment mistake that can destroy the results of years of disciplined work — and yet even experienced investors fall into it. It is not weakness; it is physiology. But it costs money.
Why the brain says "sell!"
When the market drops 20–30%, the brain activates the same mechanisms as during a physical threat. A loss hurts approximately twice as much as an equivalent gain pleases — an effect called loss aversion. Financial media dramatise, neighbours sell, the portfolio declines every day. The result is pressure to act immediately, even though the best action is to do nothing.
What happens when you sell
You realise the loss. The market has historically always recovered — after the 2008–2009 crash, after the COVID drop in 2020, after every recession. Those who stayed the course ended up in profit. Those who sold at the bottom not only missed the recovery but faced a second problem: when to buy back in? Most people wait for "calm", which arrives once the market is already high. This way the loss doubles.
How to avoid panic in advance
- Investment plan on paper: Write down in advance what you will do during a 20%, 40%, and 50% decline. An emotionally drafted plan cannot be written during the downturn — it must precede it.
- Portfolio aligned with your tolerance: If a 30% decline causes sleepless nights, you have too large an equity allocation. A properly constructed portfolio does not require intervention in a crisis.
- DCA as an anchor: Regular investments of fixed amounts buy more cheaply during a decline — the downturn becomes an opportunity, not a threat. More in the article DCA and cost averaging.
- Emergency reserve: Someone with a reserve covering 3–6 months of expenses outside investments does not have to sell due to sudden cash needs.
One extra test
Before any sale during a downturn, ask yourself: "Have the fundamentals of my investment changed, or just the price?" If nothing has changed in why you bought the ETF — the market is still diversified, companies are still operating — then panic is a poor adviser. Understanding the psychology of investing is covered in the overview on the Compound blog.
FAQ
Why is panic selling so harmful?
You realise a loss that would have erased itself without intervention over time. You also miss the market recovery and typically buy back in at a higher price. Research shows that missing the 10 best days over 20 years can reduce portfolio returns to a fraction of the original.
What should I do when the market drops 30%?
Ideally nothing — or buy more if your plan allows. Check whether the decline changes the fundamentals of your investment thesis. If not, stick to the plan. If you cannot stay the course, it is worth reconsidering your asset allocation.
How do I prepare for the next downturn now?
Write your investment plan now while things are calm — what you will do at a 20%, 40%, 50% decline. Make sure you have an emergency reserve and a portfolio matching your actual risk tolerance. Regular DCA investing helps write the answer automatically during downturns.
Is DCA protection against panic?
To some extent yes. A regular fixed-amount purchase is automatic — you do not decide "whether and how much to buy" every month. During a downturn you buy cheaper without having to consciously decide to buy in a moment of fear.