[Summary]
The sunk cost effect is the psychology of being tied to the money and time you have already invested.
Merely remembering the meaning of sunk cost effect is not enough to make actual buying and selling decisions. You need to look at the context in which the words are used.
In actual investment, we start by looking at the expected future value rather than the past investment amount. However, we cannot overlook the fact that it is easy to keep putting additional funds into loss-making stocks.
In this article, we will organize the sunk cost effect not as "knowledge" but as a step to check before buying or selling. Don't rush to conclusions, read according to your financial amount and time horizon.
First, distinguish based on sunk cost effect.
When looking at the sunk cost effect, first determine what you want to judge. The information you need will change depending on whether you want to know the meaning, confirm before buying or selling, or review your current holdings.
Especially for beginners in investing, the easier the words are, the more they tend to take them as a conclusion. The sunk cost effect is not the only factor in making decisions. If you want to check it, it is more realistic to look at it in conjunction with fund management, holding period, and opposing materials.
Putting the meaning of the sunk cost effect into practice
If we look at the sunk cost effect in terms of its meaning, we must first make a narrow premise. It is important not to mix up whether you are talking about the market as a whole, individual stocks, NISA or long-term funds.
Checking the following points will make things a lot easier.
| Axis to check | What to look at with sunk cost effects |
|---|---|
| purpose | What do you use to judge? |
| Time axis | Which is closer to short-term trading, long-term holding, or NISA? |
| basis | Which one is more important: price, business performance, interest rates, exchange rates, or psychology? |
| risk | When things go the other way, where should you look again? |
| action | Will it lead to buying, selling, or doing nothing? |
Points that can easily cause trouble in making decisions
The sunk cost effect doesn't only stumble when you don't have enough knowledge. In fact, there are situations where we interpret something conveniently because we know a little bit about it.
- Do not use the sunk cost effect definition as a buy or sell signal
- Separate the meaning, situations in which it is used, and situations in which it is not used.
- Check only one difference between similar words
- If you cannot explain it, reduce your position.
The important thing here is not to settle on a single correct answer based solely on the sunk cost effect. In investment, the meaning of the same material changes depending on the market, holding period, and amount of funds. When in doubt, prioritize confirmation over conclusion.
Checklist before buying and selling
Before using the sunk cost effect as a basis for making an actual decision, check at least these five things.
- Can you explain in one sentence the purpose of looking at the sunk cost effect?
- Have you confirmed one or more countermeasures or failure conditions?
- Are you investing your living funds or money that will be used soon?
- Have you decided in advance the criteria for cutting losses, taking profits, and continuing to hold stocks?
- Are you making judgments based only on social media or short headlines?
Checklists are simple, but they prevent you from adding reasons after making a decision. The purpose of checking the sunk cost effect is not to act faster, but to reduce unnecessary judgment errors.
Summary
The sunk cost effect is a material for organizing investment decisions. Even if you read it as a meaning, your judgment will be inaccurate if you treat it as a standalone buy/sell signal.
The points to keep in mind are as follows.
- Decide first the purpose of looking at the sunk cost effect
- Do not mix time axis and amount of funds
- Check not only good materials but also negative materials
- When using NISA and long-term funds, consider how to handle losses
- When in doubt, reduce your position or postpone it.
The more knowledge you have, the safer it seems, but in the market it can become dangerous if you use it incorrectly. It is realistic to treat the sunk cost effect as a tool to pause before buying or selling, rather than a word that forces you to make a hasty decision.