What Is a Defined Contribution Plan?
A defined contribution (DC) plan is a retirement scheme in which the employer, the employee, or both make regular contributions to an individual account, and the final retirement benefit depends entirely on investment returns. Japan's iDeCo (individual-type DC) allows annual contributions of up to 816,000 yen for self-employed individuals and 144,000-276,000 yen for company employees, depending on their employer's pension arrangements. In the U.S., the 401(k) plan permits employee contributions of up to $23,000 in 2024 ($30,500 for those aged 50 and above).
Tax Advantages and Long-Term Impact
DC plans offer triple tax benefits in Japan: contributions are fully deductible from taxable income, investment gains compound tax-free, and lump-sum withdrawals receive a retirement income deduction. For someone in the 30% marginal tax bracket contributing 276,000 yen annually, the tax savings alone amount to roughly 82,800 yen per year. Over 30 years at a 5% annual return, a 276,000 yen annual contribution grows to approximately 19.4 million yen, compared with about 14.5 million yen in a taxable account after the 20.315% levy on gains.
Key Considerations
The biggest drawback is illiquidity: iDeCo funds cannot be withdrawn until age 60. Early withdrawal is permitted only in extreme circumstances such as disability. Asset allocation within a DC plan should reflect the long time horizon; holding conservative assets like deposits inside a tax-advantaged wrapper wastes the compounding benefit. Review your allocation annually and shift gradually toward bonds as retirement approaches.