Navigating Solo 401(k) Plans: A Complete Guide for the Self-Employed

By Rebecca Lake · December 04, 2023 · 11 minute read

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Navigating Solo 401(k) Plans: A Complete Guide for the Self-Employed

Being self-employed offers many perks, including freedom and flexibility. What it doesn’t offer is an employer-sponsored retirement plan. But when you don’t have access to a 401(k) at work, opening a solo 401(k) can make it easier to stay on track with retirement planning.

Before you establish a solo 401(k) for yourself, it’s important to understand how these plans work and the pros and cons involved.

What Is a Solo 401(k)?

A solo 401(k) is a type of 401(k) that’s designed specifically with self-employed individuals in mind. This retirement savings option follows many of the same rules as workplace 401(k) plans in terms of annual contribution limits, tax treatment, and withdrawals. But it’s tailored to individuals who run a business solo or only employ their spouses.

It’s one of several self-employed retirement options you might consider when planning a long-term financial strategy.

Definition and Overview

A solo 401(k) is a tax-advantaged retirement account that’s for self-employed individuals and business owners who have zero employees, or no employees other than their spouse. This type of 401(k) plan is also known by a few other names:

•   Solo-k

•   Uni-k

•   One-participant plan

Traditional solo 401(k) contributions are made using pre-tax dollars. However, it’s possible to open a Roth solo 401(k) instead. In the case of a Roth solo 401(k), you’d make contributions using after-tax dollars and be able to withdraw the money tax-free in retirement.

A self-employed 401(k) plan works much the same as a regular 401(k). For instance, you may be able to take loans from your savings if needed. Catch-up contributions are also allowed. The biggest difference is that there is no matching contribution from an outside employer.

You can start investing in a solo 401(k) for yourself through an online brokerage. There’s some paperwork you’ll need to fill out to get the process started, but once your account is open you can make contributions year-round.

At the end of the year, the IRS requires solo 401(k) plan owners to file a Form 5500-EZ if the account has $250,000 or more in assets.

💡 Quick Tip: Look for an online brokerage with low trading commissions as well as no account minimum. Higher fees can cut into investment returns over time.

Contribution Limits in Solo 401(k) Plans

Much like workplace 401(k)s, there are annual contribution limits that apply to solo 401(k) plans.

The IRS caps total contributions to a solo 401(k) account at $66,000 for 2023 and $69,000 for 2024. That doesn’t include catch-up contributions for those age 50 and over, which are an additional $7,500 for each year.

As both the employee and employer of your own business, you can contribute both elective salary deferrals and employer nonelective contributions (you are both the employer and the employee in this scenario). Each has different contribution caps.

Annual Contribution Limits

As an employee, you can contribute up to 100% of your earned income up to the annual contribution limit: $22,500 in 2023 and $23,000 in 2024, plus an additional $7,500 for those age 50+ in elective salary deferrals.
In addition, you can make employer nonelective contributions. These come directly from the “employer” (aka you) and are not deducted from the employee’s (your) salary. As an employer, you can contribute up to 25% of your self-employment income (business income – ½ self-employment tax and elective salary deferrals), in pre-tax dollars.

Setting Up a Solo 401(k) Plan

If you’re interested in setting up a solo 401(k) for yourself, you can do so through an online brokerage. Here’s a step-by-step guide for how to open a solo 401(k).

Steps to Establish Your Plan

1. Choose a Plan Administrator

A plan administrator is the person responsible for managing your solo 401(k). It’s their job to make sure the plan is meeting reporting and other requirements established by the IRS. If you’re self-employed, you can act as your own plan administrator or you could choose your accountant instead.

2. Choose a Brokerage

Once you know who’s going to manage the plan, the next step is deciding where to open it. A number of brokerages offer solo 401(k) plans so you may want to spend some time comparing things like:

•   Account setup process

•   Investment options

•   Fees

You may be able to start the solo 401(k) account setup process online, though some brokerages require you to call and speak to a representative first. And you may need to finalize your account opening by mailing or faxing in any supporting documents the brokerage needs to complete the application.

3. Fill Out a Solo 401(k) Application

Before you can start a 401(k) account for yourself, you’ll need to give your brokerage some information about your business. A typical solo 401(k) application may ask for your:

•   First and last name

•   Employer Identification Number (EIN)

•   Plan administrator’s name and contact information

•   Social Security number

•   Mailing address

•   Citizenship status

•   Income information

You’ll also need to disclose any professional associations or affiliations that might result in a conflict of interest with the brokerage. In completing the application, you’ll be asked to name one or more beneficiaries. You may also be asked to provide bank account information that will be used to make your initial contribution to the plan.

4. Choose Your Investments

Once you’ve returned your solo 401(k) account application and it’s been approved, you can choose your investments. The type of investments offered can depend on the brokerage and the plan. But typically, you may be able to choose from:

•   Target-date funds

•   Index funds

•   Actively managed funds

•   Exchange-traded funds (ETFs)

Whether you have access to individual stocks, bonds, CDs, or alternative investments such as commodities can depend on the platform that’s offering the plan.

5. Decide How Much to Contribute

You may choose to schedule automatic investments or make them manually according to a schedule that works for you.

Choosing Between Traditional and Roth Solo 401(k)s

You can opt for a traditional solo 401(k), which is made with pre-tax dollars, or a Roth solo 401(k), which is made with after-tax dollars. Which plan is better for you may depend on what you expect your income to be in retirement.

If you believe your income will be higher in retirement than it is now, in general, a Roth could be a better choice since you can take the distributions tax-free at that time. But if you think your income may be less in retirement than it is now, you might be better off with a traditional solo 401(k), which allows you to take the tax deduction now and have your distributions taxed in retirement.

Advantages and Disadvantages of Solo 401(k) Plans

When considering retirement account options, it can be helpful to look at the pros and cons to determine what works best for your personal situation.

Benefits of Having a Solo 401(k)

There are different reasons why opening a 401(k) for self employed individuals could make sense.

•   Bigger contributions. Compared to other types of self-employed retirement plans, such as a SEP IRA or SIMPLE IRA, solo 401(k) contribution limits tend to be more generous. Neither a SEP IRA or SIMPLE IRA, for instance, allows for catch-up contributions.

•   Roth contributions. You also have the option to open a Roth solo 401(k). If you anticipate being in a higher tax bracket when you retire, you may prefer being able to withdraw contributions tax-free with a Roth.

•   Flexible withdrawal rules. A solo 401(k) can also offer more flexibility with regard to early withdrawals than a SEP IRA, SIMPLE IRA, traditional IRA, or Roth IRA. If your solo 401(k) plan allows it, you could take out a loan in place of an early withdrawal. This could help you to avoid early withdrawal penalties and taxes. An IRA-based plan wouldn’t allow for loans.

Considerations and Potential Drawbacks

There are also a few potential downsides of investing in a solo 401(k).

•   Eligibility restrictions. If you run a small business and you have at least one employee other than a spouse, you won’t be able to open a solo 401(k) at all.

•   Complicated reporting. Calculating contributions and filing can be more complicated with a solo 401(k) vs. a SEP IRA or SIMPLE IRA. If your plan has more than $250,000 in assets you’ll need to file Form 5500-EZ with the IRS each year.

•   Administrative costs. Depending on where you open a solo 401(k) plan, the cost of maintaining it year to year may be higher compared to other self employed retirement plans. And an early 401(k) withdrawal can trigger taxes and penalties.

It’s important to consider the range of investment options offered through a solo 401(k). What you can invest in at one brokerage may be very different from another. The individual cost of those investments can also vary if some mutual funds or exchange-traded funds offered come with higher expense ratios than others.

💡 Quick Tip: Did you know that you must choose the investments in your IRA? Once you open a new IRA and start saving, you get to decide which mutual funds, ETFs, or other investments you want — it’s totally up to you.

Withdrawals and Loan Provisions

There are certain requirements for withdrawals and/or loans from a solo 401(k).

Rules for Withdrawing Funds

You can make withdrawals from a solo 401(k) without penalty at age 59 ½ or older. Distributions may be allowed before that time in the case of certain “triggering events,” such as a disability, but you may owe a 10% penalty as well as income taxes on the withdrawal.

Loan Options and Conditions

Some solo 401(k) plans may be set up to allow loans. If yours does, you could take out a loan in place of an early withdrawal. This could help you to avoid early withdrawal penalties and taxes. Just be sure to find out the loan terms and conditions, which can vary by plan.

Testing and Compliance for Solo 401(k)s

Unlike workplace 401(k)s, solo 401(k)s have no testing compliance requirements involved.

Alternatives to Solo 401(k) Plans

Instead of a solo 401(k), self employed individuals can consider another type of retirement account. Here’s how different options stack up.

Comparing a Solo 401(k) to a SEP IRA and Other Retirement Options

A SEP IRA is designed for small businesses. However, unlike a solo 401(k), a SEP IRA allows no catch-up contributions and there is no Roth version of the plan.

A SIMPLE IRA is for businesses with no more than 100 employees. It has much lower contribution limits than a solo 401(k) and once again, there is no Roth option.

Pros and Cons of a Solo 401(k)

A solo 401(k) has advantages and disadvantages. Here’s a side-by-side comparison of the benefits and drawbacks.

Solo 401(k) Pros

Solo 401(k) Cons

Catch-up contributions may allow older investors to save more for retirement versus a SEP IRA or SIMPLE IRA. Only self-employed individuals who have no employees or just employee their spouses can contribute.
It’s possible to choose between a traditional solo 401(k) or Roth solo 401(k), based on your investing goals and tax situation. Annual reporting requirements may be more complicated for a solo 401(k) compared to other self employed retirement plans.
Solo 401(k) plans may allow for loans, similar to workplace plans. Early withdrawals from a solo 401(k) are subject to taxes and penalties.

The Takeaway

A solo 401(k) can be a worthwhile investment vehicle for self-employed people who want to save for retirement. It has more generous contribution limits than some other retirement options. In addition, there is a Roth version of the plan, and a solo 401(k) plan may also offer flexibility in terms of early withdrawals. For individuals who are self-employed, opening a solo 401(k) is one potential way to start saving for their golden years.

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Easily manage your retirement savings with a SoFi IRA.


Can I contribute 100% of my salary to a solo 401(k)?

As an employee, you can contribute up to 100% of your earned income to a solo 401(k) up to the annual contribution limit, which is $22,500 in 2023, and $23,000 in 2024, plus an additional $7,500 for those age 50 and up in elective salary deferrals.

Is a solo 401(k) taxable income?

You will pay taxes with a solo 401(k), but the type of plan you open determines when you’ll pay those taxes. If you have a traditional 401(k), your contributions are tax-deferred, and they reduce your taxable income for the year in which you make them. However, you will pay taxes on distributions when you take them in retirement. If you have a Roth 401(k), you pay taxes on your contributions when you make them, but your distributions in retirement are tax-free.

What is the average return on a solo 401(k)?

The return on a solo 401(k) depends on the investments in your portfolio. However, in general, a solo 401(k) invested in a mix of bonds, stocks, and cash assets can have an average rate of return ranging between 3% and 8%. But again, it depends on what your investments are, and how much you allocate to those different assets. You may want to compare your plan’s performance to plans with similar funds to get a general sense of what the average return might be.

Who qualifies for a solo 401(k)?

To be eligible for a solo 401(k), you must be self-employed or a small business owner with no employees other than a spouse. To open a solo 401(k) you will need an Employee Identification Number (EIN), which is available from the IRS.

Photo credit: iStock/visualspace

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Tax Information: This article provides general background information only and is not intended to serve as legal or tax advice or as a substitute for legal counsel. You should consult your own attorney and/or tax advisor if you have a question requiring legal or tax advice.

Financial Tips & Strategies: The tips provided on this website are of a general nature and do not take into account your specific objectives, financial situation, and needs. You should always consider their appropriateness given your own circumstances.

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