Loss aversion bias can destroy compound interest benefits

During a discussion on The Man Who Explains the Economy, Song Tae-heon warned that loss aversion bias leads investors to average down instead of cutting losses, potentially stalling the exponential growth of compound interest over a 20 to 30 year period.

What is the psychology behind investors who choose "averaging down" instead of cutting losses because they cannot accept a realized loss? Even when investment principles are established, human nature acts as the greatest obstacle to wealth formation by preventing those principles from being put into action.

In a dialogue featured on The Man Who Explains the Economy (Kim Kwang-seok TV) with expert Song Tae-heon, the discussion covered common psychological traps investors fall into and practical asset management strategies to maximize the effect of compound interest. Song pointed out that while investors theoretically understand compound interest, they fail to enjoy its magic in practice due to "loss aversion bias," a fundamental human instinct. This psychological mechanism, such as checking online discussion boards to justify averaging down instead of cutting losses even when facing a 15% deficit, acts as a powerful force that prevents investors from adhering to their principles.

"Compound interest rises exponentially; a large setback can end it"

While many investors believe that long-term investing alone will yield compound interest benefits, Song emphasized that one must note that the compound interest graph rises steeply in an exponential rather than linear form. The period where the effects of compound interest truly manifest is when the investment duration reaches 20 to 30 years. He explained that unlike the past era of high interest rates, the current world—characterized by increased life expectancy and extended retirement ages—provides the conditions to enjoy compound interest over a 30-year period while working.

The problem lies in the "losses" that occur while trying to maintain this upward curve. "If you incur a loss while climbing a mountain, you are pushed backward," Song explained. "If you are pushed back significantly once, it takes too much time to climb back to the previous height, resulting in an outcome no different from simply leaving money in a safe and letting time pass." Citing Warren Buffett's first principle, "Never lose money," he emphasized that the core of compound interest investing is not merely accumulating time, but must be supported by defensive techniques to avoid large losses. This is because losing a significant portion of assets forces an investor into extreme situations: either taking even greater risks to earn large sums or having to start the accumulation of time all over again.

"A strategy easier than a salary increase: 8.2% returns using tax benefits"

As the first step to growing assets, Song suggested "increasing the investment principal." He defined true wealth management as executing tasks starting from the one an individual is most likely to practice, categorizing the core of financial technology into managing investment principal, managing return rates, and managing investment duration. While increasing income is theoretically clear, it is difficult to execute. Therefore, he advised using credible data, such as the Survey of Household Finances and Living Conditions from Statistics Korea, to understand one's own income and expenditure structure. He added that it is particularly important to understand the structure of income excluding "non-consumption expenditures" that are difficult for individuals to manage, such as taxes, National Pension, health insurance, and loan interest.

Song emphasized that utilizing tax credit products (such as pension savings, IRP, and ISA) through year-end tax adjustments is the most efficient form of wealth management. He analyzed that receiving tax refunds through investment is an act of increasing actual disposable income, which has an effect equivalent to approximately an 8.2% return when converted to bank deposit yields. "Securing tax benefits is equivalent to securing unconditional returns, so missing out on them is like paying more tax than necessary," he said. He explained that the refunds generated through these tax-benefit products should be viewed as future cash flow, and if accumulated over 30 years, the difference in wealth can be enormous due to the effect of compound interest.

Priority between studying macroeconomic indicators and the basics

The dialogue continued with a discussion regarding the utility of studying macroeconomic indicators. Kim Kwang-seok suggested that following the United States Consumer Price Index (CPI) or Producer Price Index (PPI) is part of the "expert domain," essential for judging the possibility of interest rate hikes or cuts and determining appropriate investment timing. This perspective views such data analysis as a direct tool for asset management.

In response, Song advised that while macroeconomic analysis is useful for understanding the world, the priorities for general investors are often reversed. "It is like a person who does not know how to swim attempting to cross the Han River after watching someone else do it," he said, emphasizing that instead of clinging to high-level analysis, it is more important to first build the "basics of money," such as income management and utilizing tax benefits. His point was that a basic asset management system must be established before handling high-level information.

Ultimately, the core of this discussion is that the success or failure of an investment depends not on flashy economic indicator analysis, but on the fundamental strength to create an environment where compound interest can operate by minimizing losses.

Source: original video (YouTube)