One-Participant 401(k)

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One-Participant 401(k) plans, also known as Solo 401(k)s, are retirement savings vehicles tailored for self-employed individuals and business owners with no employees. This powerful tool allows entrepreneurs to harness the benefits of a traditional 401(k) without the need for a larger business structure. This article will explore the benefits, rules, and strategies for maximizing retirement savings with a One-Participant 401(k) plan.

What is a One-Participant 401(k)?

A One-Participant 401(k) is a tax-advantaged retirement savings plan available to self-employed individuals and business owners with no full-time employees other than themselves and their spouse. This plan allows for higher contribution limits compared to other retirement options for the self-employed, like SEP IRAs or traditional IRAs.

Key Features

  • High Contribution Limits: Combines employee elective deferrals and employer profit-sharing contributions.
  • Tax Benefits: Contributions reduce taxable income and investments grow tax-deferred.
  • Flexibility: Offers Roth (after-tax) contributions and loan options, depending on the plan.

Benefits of a One-Participant 401(k) Plan

  1. Increased Savings Potential: Allows total contributions as both employer and employee, significantly increasing the maximum allowable contribution.
  2. Tax Efficiency: Provides upfront tax deductions and deferred taxation on earnings, which can be substantial for high earners.
  3. Loan Provisions: Participants may borrow against their savings, subject to certain IRS rules.

Setting Up a One-Participant 401(k) Plan

  • Establishing the Plan: Requires setup through a financial institution that offers Solo 401(k) plan services.
  • Plan Documents: It’s critical to maintain proper documentation, including a written plan and annual reporting if assets exceed $250,000.
  • Deadlines: The plan must be established by the employer’s tax filing deadline (including extensions) for the year in which the initial contributions will be made.

Contribution Rules and Limits

  • Contribution Types: As an employee, you can make elective deferrals. As an employer, you can make profit-sharing contributions.
  • Annual Limits: For 2023, the elective deferral limit is $20,500 ($27,000 if age 50 or over), and the total contribution limit including profit-sharing is $61,000 ($67,500 with catch-up contributions).

Investment Options and Management

  • Diverse Investments: Participants can typically choose from a variety of investment options, similar to traditional 401(k) plans.
  • Control: Offers more control over the investments compared to SEP or SIMPLE IRA plans.

Tax Implications

  • Deductions: Contributions can be deducted from your taxable income.
  • Roth Option: Allows for after-tax contributions with tax-free growth and withdrawals for qualified distributions.

Maximizing the Benefits of a One-Participant 401(k) Plan

  • Maximize Contributions: Aim to contribute as much as possible within the limits to maximize the tax benefits and retirement savings.
  • Tax Planning: Consider the timing of contributions and withdrawals for optimal tax advantages.
  • Investment Strategy: Develop an investment strategy that aligns with your risk tolerance and retirement timeline.

Comparing to Other Retirement Plans

  • SEP IRAs: Typically have lower contribution limits and do not allow for Roth contributions or loans.
  • Traditional IRAs: Have much lower contribution limits and income-based restrictions for tax-deductible contributions.

Challenges and Considerations

  • Administrative Responsibilities: You are responsible for ensuring that the plan complies with legal requirements.
  • Record-Keeping: Requires diligent record-keeping and understanding of complex tax rules.


Q: Who is eligible for a One-Participant 401(k) plan? A: Self-employed individuals and business owners with no employees other than themselves and their spouse.

Q: Can I contribute to a Solo 401(k) if I have other retirement plans? A: Yes, but the total contributions across all plans must not exceed IRS limits.

Q: What are the reporting requirements for a One-Participant 401(k) plan? A: If plan assets exceed $250,000, IRS Form 5500-EZ must be filed annually.


The One-Participant 401(k) plan is an excellent retirement savings option for self-employed individuals, offering high contribution limits, tax benefits, and investment flexibility. Understanding and utilizing this plan effectively can significantly enhance your retirement savings and provide financial security in your later years.

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