Myopic Loss Aversion
The tendency to evaluate a long-term portfolio too frequently, magnifying the felt pain of short-term losses.
How it is identified
Test: the probability of observing a loss rises sharply as the evaluation interval shortens, while the underlying investment is unchanged
Unit
qualitative
In depth
The mechanism is arithmetic: over a single day equity returns are close to a coin flip, so a daily checker sees losses roughly half the time, while an annual checker sees them perhaps a quarter of the time and a five-yearly checker rarely. Combining that with loss aversion means frequent evaluation produces more felt pain from the same investment, which is why frequent checkers hold less equity and abandon plans more often. This is the strongest behavioural argument for not looking at a long-term portfolio daily. It is also the explanation Benartzi and Thaler proposed for why the equity risk premium is as large as it is.
Worked example
An investor checking daily sees a loss on roughly 46% of days; checking annually, on roughly a quarter of years. The portfolio is identical, and the second investor experiences a fraction of the discomfort.
Illustrative figures, chosen so the arithmetic is easy to follow. Not a live price and not a valuation of any company.
Educational reference only
This entry explains what “Myopic Loss Aversion” means. It is not investment advice and not a recommendation to buy or sell any security. Any numbers above are illustrative, not live prices, and nothing here predicts price direction or rates a stock. Consider your own circumstances and consult a SEBI-registered investment adviser before acting.