When the short-term nature of markets collides with the long-term goals of investors, the market wins the attention war and investors lose…when they act on it.
Excessive action (trading) leads to worse returns, says the research. And selling to avoid losses, when your portfolio is a sea of red, is often a result of myopic loss aversion.
That’s a fancy way of saying that investors who check their portfolios often are more likely to see losses, and mistakenly act on it. In addition, they allow their aversion to losses to affect their portfolio allocation. They shift their portfolio to a larger holding of bonds and cash when it should be in stocks and they earn less money over time.
Bill Miller explained it further in his 1995 commentary: Continue Reading…

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