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Home / Investing / Retirement / How To Open A Solo 401k (Traditional And Roth)

How To Open A Solo 401k (Traditional And Roth)

Updated: August 8, 2024 By Robert Farrington | 8 Min Read 19 Comments

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How To Open A Roth Solo 401k
how to open a solo 401k

Opening a solo 401k for your small business can make a lot of sense financially. When you're self employed, the solo 401k allows you to save the most money versus all of the other self employed retirement plans (SEP-IRA, SIMPLE IRA, Keogh Plan). It is even better if you and your spouse run your business together, because you can save even more with your spouse.

But setting up and opening your solo 401k plan can be confusing. There are a lot of options to consider, and you want to select a plan that offers flexibility for the future. Unlike a SEP-IRA, there is a lot more paperwork to fill out, and there are more potential fees to consider.

Here's how to open a solo 401k and what options you should select.

Table of Contents
Things To Consider When Opening A Solo 401k
Prototype Plan Vs. Custom Plan
Should You Do A Roth Solo 401k?
Selecting A Brokerage Firm For Your Solo 401k
What Paperwork You Need To Fill Out To Open Your Account
Ongoing Considerations For Your Solo 401k
Conclusion

Things To Consider When Opening A Solo 401k

If you're considering opening a solo 401k, there are a few things to consider when it comes to plan features.

There are five key areas that you need to decide before you open your solo 401k:

  1. Will you have both Traditional and Roth Solo 401k contributions?
  2. Will you allow loans from your solo 401k plan?
  3. Can you do rollovers into the plan?
  4. What are the fees for maintaining the plan?
  5. Do you want to invest in alternative investments, like real estate or cryptocurrency?

Everyone who opens a solo 401k will have different requirements. However, I would recommend you open a solo 401k plan with the most options and flexibility. While you can always amend your plan documents, it can be a hassle and can cost you money (potentially). As such, it makes sense to create a solo 401k plan with the most options up front.

Prototype Plan Vs. Custom Plan

Once you understand what options you want for your solo 401k plan, it's time to discuss plan documents.

See, your solo 401k really has two parts:

  1. The Solo 401k Plan Documents (also called an Adoption Agreement) - this is what spells out what options your solo 401k offers
  2. The brokerage documents/application - this is what your brokerage firm needs to open accounts in the name of the 401k

When it comes to the solo 401k plan documents, you can either use a prototype plan, or create your own custom plan.

A prototype plan is typically offered by the brokerage firms that offer free solo 401k plans. They are called prototype plans because they are very generic plans that were created by a lawyer, and anyone can use them. However, because these are generic plans, they might not offer all of the options you're looking for in a solo 401k.

For example, Fidelity's solo 401k plan doesn't offer a Roth solo 401k option. Vanguard's solo 401k plan doesn't offer loans from your 401k. As such, you need to carefully consider the options available in a prototype solo 401k. E*Trade offers the most robust prototype solo 401k plan.

On the other hand, you can create a custom solo 401k plan. This is where you pay a company to draft you plan documents that are custom to your needs. The reason you create this is because you want to invest in alternative assets like real estate.

Our recommendation for a company that does this currently is MySolo401k.net. This company will create a solo 401k document that you can then use to administer your plan. It allows for much more flexibility, but you will pay a fee upwards of $525 for the first year, then an annual fee of $125 per year. Read our full review here.

Other options include:

  • RocketDollar: $600 for the first year, then $240 per year. Read our review here.
  • Ubiquity: $295 setup fee, then 19 per month. Read our review here.

Should You Do A Roth Solo 401k?

One of the options that's become important is allowing for a Roth solo 401k. Surprisingly, many brokerage firms currently don't allow a Roth solo 401k, but it can be a valuable option.

When it comes to your solo 401k, it's important to remember that you have two aspects of contributions to your plan:

  1. You have your elective deferrals, which can either be Roth or Traditional
  2. You have your profit sharing contribution, with can only be Traditional

Where a Roth option comes in handy is if you're looking for tax diversification. With Roth contributions, you are using post-tax money. So, you will pay more in taxes today, but you will pay less in the future. However, if you're putting in large profit sharing contributions into your solo 401k, then it might make sense to make Roth contributions.

The reason? It will give you tax diversification in retirement. You can choose whether you use taxable or tax free money in the future - and options are always great.

The important thing to remember here is options. You just want the options to be able to invest how you choose.

Selecting A Brokerage Firm For Your Solo 401k

When selecting a brokerage firm for your solo 401k, you want to select the firm that offers the most options.

If you're okay with a prototype plan, you can use our Solo 401k Brokerage Comparison to see which major firms offer the options you're looking for.

If you're using a custom solo 401k plan, you need to take your solo 401k documents to the brokerage of your choice and they will open a custodial account on your 401k's behalf. Some firms offer this service, and others don't. For example, Fidelity and Charles Schwab are two brokerage firms that allow for customers to use third-party 401k plans with their brokerage services.

However, when using a third party plan, it adds to the complexity of using a solo 401k. For instance, as a custodial account, the firm will not keep track of your trades and investments - that's your responsibility. If you need to fill out tax forms, such as a 1099-R, these firms will not help you. You either have to do it yourself, or pay someone to do it for you.

We decided to go with ETrade for our Solo 401k because they had the most robust free plan.

What Paperwork You Need To Fill Out To Open Your Account

I was surprised at how much paperwork is required to open a solo 401k account. You'd think it would be simple, with very common forms to fill out. However, it's completely the opposite. It becomes even more challenging if you add a Roth solo 401k, and you have to do double the paperwork if you're adding a spouse to your plan.

When opening your solo 401k plan, you will need to create the following documents. You will need to create separate plan documents for both your Traditional and Roth Solo 401ks. They are both considered separate plans for tax purposes.

Plan Documents For Traditional Solo 401k

  • 401k Plan Adoption Agreement
  • Designation of Successor Plan Administrator (notary or witness required for this form)

Plan Documents For Roth Solo 401k

  • 401k Plan Adoption Agreement (make sure you include a section about taxable movement of funds from Traditional to Roth 401k if desired)
  • Designation of Successor Plan Administrator (notary or witness required for this form)

Required Documents For Individual

  • Brokerage Account Application for 401k Account
  • Brokerage Account Application for Roth 401k Account
  • Designation of Beneficiary Form for Account (for both accounts)
  • Power of Attorney (if desired, for both accounts)

Required Documents For Spouse

  • Brokerage Account Application for 401k Account
  • Brokerage Account Application for Roth 401k Account
  • Designation of Beneficiary Form for Account (for both accounts)
  • Power of Attorney (if desired, for both accounts)

When you're done with all these documents, you'll have two solo 401k plans, and 4 accounts (a traditional and Roth solo 401k account for each spouse).

Ongoing Considerations For Your Solo 401k

One of the great things about a solo 401k is that they are relatively easy to maintain, for the most part. Since you are technically the administrator of your own plan, you are personally required to submit required filings for the plan.

There are two ongoing paperwork requirements that you will need to stay on top of. First, if your plan has over $250,000 in assets on the last day of the plan year, you have to file a form 5500. This can be a bit complicated, but if you can fill out all of that paperwork above, you can likely handle it yourself.

You can submit the IRS Form 5500 for free, electronically here: EFAST2 Filing From The IRS.

If you don't want to do it yourself, you'll need your CPA to handle this for you, and they'll likely charge a fee to do it. However, if you're using a non-prototype plan, most of the plan providers will help you prepare the Form 5500 each year as part of your annual fee.

The second form you need to keep in mind is a 1099-R, but that form is only required if you take distributions from your 401k plan or if you roll it over, withdraw money of any kind, or change providers. This form is also relatively easy to fill out, but there is no free electronic filing for this form. You either have to pay a service to file it, or mail it in yourself.

Conclusion

A solo 401k can be a great way to save for retirement if you're self employed. A Roth solo 401k adds even more flexibility to your potential retirement savings. But filling out the paperwork to open a solo 401k can be tedious and time consuming.

If you're considering a solo 401k plan, make sure that you setup a plan that offers flexibility for your needs over time.

Editor: Clint Proctor Reviewed by: Chris Muller

Robert Farrington
Robert Farrington

Robert Farrington is the founder of The College Investor and is widely recognized as one of the nation’s leading voices on student loan debt and saving for college. He holds an MBA from UC San Diego Rady School of Management and has spent over 15 years researching, writing, and advising on student loans, 529 plans, financial aid programs, and saving and investing for young professionals.

Robert has been featured in the The New York Times, The Wall Street Journal, The Washington Post, NBC News, and Forbes, where he has been a regular personal finance contributor for over a decade. His work combines both professional expertise and personal experience – he successfully navigated his own student loan repayment journey and has helped thousands of readers do the same.

He is committed to making the intersection of personal finance and education transparent and accessible. You can learn more about Robert on the About Page or on his personal site RobertFarrington.com.

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