Investment decisions may become difficult when an investor has already invested money in an investment that is declining in value. The sunk cost fallacy describes a situation where past investment costs continue to influence a current decision, even though those costs cannot be recovered. In investing, this may lead an investor to continue holding a stock or mutual fund whose value has fallen mainly because a significant amount has already been invested. The behaviour is not limited to new investors. Past experiences, emotional responses and the desire to avoid accepting a loss may influence decisions across different stages of investing.
The Psychology Behind the Sunk Cost Fallacy
The sunk cost fallacy occurs when a cost that has already been incurred influences a decision about what to do next. Since the funds have already been invested, they cannot be recovered simply by continuing with the same decision.
Consider an investor who purchases shares worth ₹50,000. The value later falls to ₹35,000. The ₹15,000 reduction represents an unrealised loss, while the ₹50,000 purchase amount is already part of the investment history.
The current decision, however, relates to whether the investment remains worth holding at its present value. The original purchase price does not determine what the security may be worth in the future.
The psychological difficulty arises when the investor focuses on recovering the ₹50,000 rather than reassessing the investment using current information. The purchase price then becomes an important mental reference point.
This may also lead to escalation of commitment. An investor may continue holding a losing investment or put additional funds into it because exiting would mean accepting that the earlier decision did not work as expected.
For example, an investor may purchase a stock at ₹600 and later see it trading at ₹400. Instead of reviewing the company based on its current financial position, the investor may focus on waiting for the price to return to ₹600.
The expectation of recovering the original amount may therefore become more important than the reasons for holding the stock today.
The bias may also involve emotional factors. A realised loss makes the outcome of an earlier decision visible. Continuing to hold the investment may feel less final because the loss remains unrealised.
This is why the sunk cost fallacy is not simply about owning an investment that has fallen in value. The important factor is whether the fund already committed is influencing the current decision.
Why Investors Struggle to Walk Away from Losing Positions
Several behavioural factors may make it difficult to reassess a losing investment. These factors often overlap and may reinforce one another.
Emotional attachment to the original decision
Investors may spend considerable time researching a stock, mutual fund or sector before investing. They may also develop confidence in their initial analysis.
When the investment later performs poorly, selling it may feel like accepting that the original analysis was incorrect. This may shift attention from the current investment case to the decision that was made earlier.
Desire to recover the investment amount
A falling investment may create a strong focus on recovering the original amount. For instance, an investor with a ₹20,000 unrealised loss may continue holding a security mainly because selling it would make the loss visible.
The amount already lost does not, by itself, determine whether the investment remains relevant. The current investment case needs to be considered separately.
Loss aversion
Loss aversion refers to the tendency for losses to have a stronger psychological effect than comparable gains. In investing, this may make investors more uncomfortable with realising a loss.
Loss aversion and the sunk cost fallacy are related but different concepts. Loss aversion concerns the psychological response to losses. Sunk cost thinking involves allowing an unrecoverable past cost to influence a current decision.
Confirmation bias
An investor holding a losing position may focus more on information that supports continuing to hold it. Positive news about a company or sector may receive greater attention, while information that challenges the original investment view may receive less attention.
This may make an objective reassessment more difficult.
Escalation of commitment
Another possible response is to put more fund into the same investment after its value falls. An investor may do this because the earlier amount has already been committed.
For example, buying additional shares at a lower price reduces the average purchase price. However, the mathematical reduction in average cost does not change the company's financial position or the reasons behind the original investment.
The reason for the additional investment therefore matters. A decision based on current information is different from adding fund mainly to recover a previous loss.
Together, these factors explain why investors may find it difficult to walk away from losing positions. The decision involves not only the investment itself but also the psychological impact of the earlier decision.
Real-World Examples of the Sunk Cost Fallacy in Investing
The following examples may provide more context on sunk cost meaning and show how sunk cost thinking may appear in common investment situations.
Holding a falling stock
An investor purchases shares of an Indian company at ₹600 after reviewing its business and financial performance. The share price later falls to ₹400 following changes in the company's operating environment.
The investor continues holding the shares mainly because selling at ₹400 would mean accepting a ₹200 loss per share.
The fall in price alone does not establish whether the investment needs to be changed. The behavioural issue arises when the original ₹600 purchase price becomes the main reason for continuing to hold the shares.
Adding more capital to a losing stock
Suppose an investor purchases 100 shares at ₹500 each. The price later falls to ₹350. The investor then purchases another 100 shares mainly because the earlier investment has already lost value.
The second purchase lowers the average acquisition price to ₹425 per share. However, the lower average price does not change the underlying business or market conditions.
The additional ₹35,000 therefore needs to be assessed as a separate investment decision rather than being justified by the ₹50,000 already invested.
Holding an underperforming mutual fund
An investor may continue holding a mutual fund after a prolonged period of weaker performance because the investment has been held for several years.
The investor may feel that selling now would make the earlier investment period feel wasted. However, the length of time already spent in a scheme is a historical factor. It does not by itself determine whether the scheme remains relevant.
The same issue may arise when a large accumulated investment makes an investor reluctant to reassess the fund.
Evidence on Related Behavioural Biases Among Indian Retail Investors
Research on Indian retail investors provides evidence of behavioural patterns involving gains and losses. A Securities and Exchange Board of India (SEBI) study on retail investor behaviour discussed the disposition effect, which refers to the tendency to sell assets with gains while continuing to hold assets with losses. The study covered the period from 1 January 2005 to 30 June 2006. It reported trading losses of ₹8,376 crore and estimated losses of ₹20,700 crore after including commissions, transaction taxes and other costs. These figures relate to the historical study period and are not current market statistics.
The disposition effect is related to sunk cost thinking, but the two concepts are not identical. The disposition effect specifically describes the tendency to realise gains while retaining losing investments. The sunk cost fallacy refers more broadly to allowing an unrecoverable past cost to influence a current decision.
A separate study using a large representative sample of Indian retail equity investors examined the relationship between investment experience, returns and investor behaviour. The researchers found that investment experience and feedback from investment returns influenced investor behaviour, including trading activity and disposition bias.
These findings do not mean that every Indian investor who holds a losing investment is affected by the sunk cost fallacy. They indicate that behavioural patterns involving past returns, gains and losses have been observed among Indian retail investors.
How to Avoid the Sunk Cost Fallacy in Your Investment Decisions
The following steps provide a structured way to separate past investment costs from the current decision.
Step 1: Separate the Past Cost from the Current Decision
Start by identifying how much has already been invested. Treat this amount as part of the investment history rather than as the main reason for continuing with the investment.
The purchase price remains relevant for calculating the gain or loss. However, the current decision needs to consider the investment's present position and available information.
Step 2: Revisit the Original Investment Reason
Review why the investment was made in the first place. The original reasoning may have involved the company's financial performance, valuation, business prospects, sector conditions or the role of the investment within the portfolio.
The purpose is to check whether those reasons remain relevant rather than assuming that the original decision must continue indefinitely.
Step 3: Identify What Has Changed
Review what has happened since the investment was made.
For a stock, this may include changes in revenue, profitability, debt, management, competition, regulation or business conditions. For a mutual fund, the review may include its portfolio, investment approach and performance against the relevant benchmark.
This helps distinguish a change in market price from a change in the factors that originally supported the investment.
Step 4: Consider the Investment at Its Current Value
An investor may temporarily set aside the original purchase price and ask whether the investment would still appear relevant based on its current price and available information.
For example, if a stock purchased at ₹500 is now trading at ₹350, the ₹500 purchase price remains part of the investment's history. It does not establish that ₹500 is the appropriate reference point for a new decision.
This approach helps reduce the influence of the original amount when reviewing the current position.
Step 5: Assess Additional Investment Separately
Any decision to add fund to a losing position needs its own rationale.
Suppose an investor has ₹30,000 invested in a stock and is considering another ₹10,000. The additional ₹10,000 may be assessed independently.
The fact that ₹30,000 has already been invested does not, by itself, provide a reason to commit another ₹10,000. The additional investment needs to be considered using current information.
Step 6: Consider the Opportunity Cost
Capital held in one investment is not available for other uses at the same time. An investor may therefore consider the alternative uses of the capital before continuing with a position.
This does not mean that every losing investment needs to be sold. Instead, opportunity cost provides another perspective for reviewing whether the existing allocation remains relevant.
Step 7: Review the Investment Periodically
Periodic reviews may help investors identify whether the original investment rationale remains relevant.
The review may include the company's financial performance, valuation, business developments, changes in the sector and broader market conditions. For mutual funds, the review may also cover portfolio changes and performance against the relevant benchmark.
A regular review also helps prevent the original purchase decision from becoming the only basis for future decisions.
Conclusion
Past investment decisions may continue to influence how investors respond when an investment loses value. The sunk cost fallacy reflects one such behavioural pattern, where fund already committed affects a current investment decision. Research involving Indian retail investors has also documented related behavioural patterns involving gains, losses and investment experience. Separating past costs from current information provides a useful framework for reviewing a losing position. Looking at the original investment rationale, changes since the investment was made and the basis for committing additional capital may help investors examine whether past costs are influencing their present decisions.
FAQs on Sunk Cost Fallacy
Why is it so hard to walk away from a bad investment?
Losses may create emotional discomfort, while the desire to recover the original amount may make investors reluctant to close a losing position.
Is the sunk cost fallacy the same as loss aversion?
No. Loss aversion concerns the response to losses, while sunk cost thinking involves allowing unrecoverable past costs to influence current decisions.
What is the disposition effect in investing?
The disposition effect refers to selling investments with gains while continuing to hold investments that have incurred losses.
Can I train myself to avoid the sunk cost fallacy?
Regular reviews, questioning the original rationale and separating past costs from current information may help reduce the influence of sunk cost thinking.
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