This article takes about 5 minutes to read

The Theory of Age-Based Risk Tolerance - Human Capital vs. Financial Capital

An investor's total wealth comprises financial capital (current savings and investments) plus human capital (the present value of future labor income). A 22-year-old new graduate may have near-zero financial capital, yet their human capital - the present value of lifetime earnings of 200-300 million yen - exceeds 100 million yen.

Human capital resembles a bond in character. It delivers stable monthly salary income and can be viewed as a low-risk asset. When human capital is large (in youth), allocating financial capital to high-risk assets (3x ETFs) keeps total-wealth risk within acceptable bounds.

As age increases, human capital declines (fewer working years remain) while financial capital grows. At age 60 upon retirement, human capital drops to zero and financial capital alone must fund living expenses. Holding high-risk assets like 3x ETFs at this stage means exposing the majority of total wealth to risk.

20s - Aggressive Investing Backed by Human Capital

The 20s represent the period when human capital is at its maximum and financial capital losses can be recovered through future labor income. Even a total loss of 3 million yen in 3x ETFs can be recovered in under a year of savings on a 5-million-yen salary. This recovery capacity justifies aggressive risk-taking.

The recommended allocation is 20-30% of investable assets in 3x ETFs, with the remaining 70-80% in index funds (global equities or S&P 500). Investing 20% of monthly income with 5-6% directed to 3x ETF contributions is a practical framework.

Contributing 30,000 yen monthly to 3x ETFs at +25% annualized (close to TQQQ's 10-year historical average) would grow to approximately 40 million yen by age 30. The same amount in the S&P 500 at +10% would reach approximately 6 million yen. Compounding acceleration is maximized over the long investment horizon available in one's 20s.

However, +25% annualized is a historical figure and not guaranteed. The possibility of an -80% crash must be priced in, and the fundamental prerequisite is limiting exposure to an amount whose total loss would not disrupt daily life.

30s - Family Formation and Risk Adjustment

The 30s concentrate major life events: marriage, children, and home purchase. These require substantial outlays, necessitating a reduction in 3x ETF allocation to 15-20% while securing liquid assets.

Running a home down-payment (20% of property value; 6 million yen on a 30-million-yen property) in 3x ETFs is dangerous. Move the down-payment portion to safe assets 2-3 years before the planned purchase, and run 3x ETFs only with surplus funds whose loss would not affect the purchase.

Children's education costs (10-20 million yen per child through university) must also be considered. Education savings should use index funds in tax-advantaged accounts, not 3x ETFs. Position 3x ETFs strictly as an 'accelerator for surplus capital.'

40s - Core-Satellite in the Accumulation Phase

In the 40s, income approaches its peak and financial assets have grown to 20-50 million yen. Reduce 3x ETF allocation to 10-15%, positioning it as the 'satellite' in a core-satellite strategy.

The core (85-90%) consists of index funds 60%, bonds 20%, and REITs 5%. The satellite (10-15%) goes to 3x ETFs. Under this structure, even an -80% crash in 3x ETFs limits portfolio-level losses to -12%.

In the 40s, even a 10% allocation represents 3-5 million yen in absolute terms. If this grows to over 10 million yen through 3x ETF compounding over five years, it provides significant retirement cushion. A balanced strategy that captures compounding benefits while controlling risk.

50s - Retirement Preparation and Gradual Reduction

The 50s are 10-15 years from retirement. Human capital's residual value is declining rapidly, and dependence on financial capital is rising. Reduce 3x ETF allocation to 5-10% and design a glide path that decreases by 1-2% annually.

A schedule of 10% at age 50, 5% at 55, and 0% at 60 is one guideline. Redirect the reduced allocation to index funds and bonds, gradually lowering overall portfolio risk.

Allocating 5 million yen to 3x ETFs at age 50 and achieving +20% annualized over five years would grow it to approximately 12.45 million yen. Locking in this profit at 55 and moving to safe assets adds 7.45 million yen to retirement funds. A strategy that captures the final burst of compounding acceleration.

However, encountering an -80% crash in the 50s could require 5-7 years for recovery. Given the risk of not recovering before the target retirement date, strictly limit exposure to an amount that would not affect retirement plans even in the worst case.

60s - Complete Exit from 3x ETFs

The 60s mark the drawdown phase, where financial capital funds living expenses. The 3x ETF allocation should be zero. After retirement, recovery through labor income is difficult, and a large loss means a permanent reduction in living standards.

If still holding 3x ETFs at age 60, sell the entire position before retirement. For tax efficiency, selling in the year before retirement (while income is still available for loss offsets) is advantageous.

A typical post-retirement portfolio targets 40-50% index funds, 40-50% bonds, and 10% cash. The annual withdrawal rate follows the 4% rule to ensure asset longevity of 30+ years. Leave the compounding power of 3x ETFs to younger generations and focus on stable withdrawals in the 60s.

Coordinating with Life Events

Regardless of age, temporarily reduce 3x ETF allocation before major life events. Two years before a home purchase, three years before a child enters university, or during a job transition - whenever a large near-term expenditure is certain, scale back 3x ETFs and secure liquidity.

Conversely, windfalls such as bonuses or inheritances present opportunities for additional 3x ETF investment. However, deploy over 3-6 months rather than lump-sum to mitigate the risk of buying at a peak.

The core of lifecycle investing is thinking in terms of total wealth: human capital plus financial capital. 3x ETFs are merely a fraction of financial capital, and it is the enormous safe asset of human capital that enables aggressive risk-taking in youth. Facing the reality that human capital diminishes with age, and disciplining yourself to systematically reduce 3x ETF exposure, is what determines lifelong wealth-building success.

Strategies for long-term wealth building are explored in a range of books on Amazon.