Prohibited Transactions Solo 401k

Self-Directed Solo 401k Prohibited Transactions Review and Illustrations


Even though you can invest your solo 401k (referred by other names such as small business 401k, self-employed 401k, owner only 401k, Solo K, etc.) in many types of alternative investments (e.g., real estate, notes, LLC, Gold, etc.), you still must be careful not to engage in prohibited transactions when investing your Solo 401k. A transaction is deemed prohibited if it benefits you, as trustee/participant of the Solo 401k plan, or other disqualified persons such as your beneficiary, spouse, son, daughter, father or mother, to name a few.

Simply stated, any transaction that does not only benefit your solo 401k, but instead you personally or someone you know who is defined as a disqualified individual by the IRS will be deemed prohibited.


Prohibited transactions are often referred to as “self-dealing.”

This means your Solo 401k/self-directed 401k is prohibited from engaging in transactions that benefit you, your direct family, or your business. The negative consequences to your Solo 401k include tax penalties and loss of tax deferred status. Simply put, prohibited transactions are investments or forms of self-dealing that would put the government at risk of losing its tax on the solo 401k. To be clear, prohibited transactions only occur when funds within your solo 401k are used improperly. You can always withdraw from your solo 401k, pay the tax (and penalty if you are under 591/2 and no exceptions apply) and spend the money any way you wish, because now the government got their tax and the money you are spending is no longer solo 401k money. They worry when you spend money within your solo 401k on certain items because they think you might just be planning to beat them out of the tax that you would have paid on a solo 401k distribution.

Prohibited transactions examples

Real estate

The rules prohibit your Solo 401k / Self-Directed 401k retirement account from holding property in which you or disqualified persons currently occupy or plan to occupy. In other words, the property must be for investment purposes only.


A lease between Solo 401k plan and daughter of Solo 401k plan trustee

Matt’s Solo 401k owns an apartment building. One of the tenants is his daughter Susan. As a party-in-interest, Susan’s leasing of the apartment is a prohibited transaction because the apartment is Solo 401k asset.

Private company

Your Solo 401k / self-directed 401k can’t purchase private shares (for example, company shares that are not traded in a public exchange such as New York Stock Exchange or NASDAQ) in your own business or of a disqualified person (e.g., your son, daughter, father and mother to name few).


The purchase of shares by Solo 401k in your own corporation

John personally owns 15% interest in a private corporation that he manages. Two years later he decides to use his Solo 401k plan to purchase Nick’s, another shareholder, 20% worth of shares. This is a prohibited transaction because John already owns and manages the corporation.

Promissory notes

You can’t loan your Solo 401k or self-directed 401k funds to a disqualified person such as your father, mother, son, or daughter for example.


promissory note to daughter

Tina loans $50,000 from her Solo 401k to her daughter charging her 10% interest per year. This is considered a prohibited transaction because Tina’s daughter is considered a disqualified person.

Roundabout transactions

A roundabout transaction occurs when the Solo 401k participant/trustee structures one or more transactions with the purpose of making a prohibited transaction.

For example, you loan money from your Solo 401k /self-directed 401k to your friend (who’s not a disqualified person), and he or she then turns around and loans the same funds to your mother. This is considered a roundabout transaction and viewed by the IRS as not only prohibited but also as an attempt to evade the tax rules because you can’t loan money from your Solo 401k to your mother, even if you first loan it to your friend (who’s not a disqualified person), who then loans it to your mother.

Disallowed investments

For the most part you can invest your Solo 401k / self-directed 401k in any investment type with the exception of the following:


A collectible includes a work of art, rug, antique, metal, gem, stamp, certain coins, alcoholic beverage, and musical instruments to name a few. The U.S. Treasury has the power to add to this list any other tangible personal property.

Click here to read our blog about the negative tax consequences of investing your Solo 401k in collectibles.

Disqualified persons

A “disqualified person” is defined as a fiduciary, you, a member of your family or any other entity such as a corporation, partnership, trust or estate that is 50% or more controlled by you or your family members.

For a solo 401k plan, you, the solo 401k owner, are a fiduciary. This is because you have discretion and control over the plan’s investments. In other words, you can’t blame it on the bank or solo 401k provider. If you misuse your solo 401k plan, it’s your fault.

The IRS considers the following as disqualified persons with respect to Solo 401k / self-directed 401k transactions:

  • Family members such as your father, grandmother (considered ancestors)
  • Your children, grandchildren (considered lineal descendents)

For a full list of disqualified persons visit here 

Tax Consequence of prohibited transaction

Whether you intentionally or accidentally subject your Self-Directed Solo 401k to a prohibited transaction, the tax consequences are the same—your Solo 401k will generally be subject to federal taxes, possible state taxes and penalties.

In sum, thread carefully when investing your Solo 401k, also commonly referred to as a Self-Directed Solo 401k, Self-Directed 401k, Individual 401k, Individual K, Single K, Single 401k or Self-Employed 401k, because of the many different possible ways of structuring alternative investments such as real-estate, private investments, promissory notes, etc.

Additional Information on Prohibited Transactions

The prohibited transaction rules are found both in the Internal Revenue Code (IRC) and in ERISA.

Click here to learn about prohibited transactions under ERISA.

To learn about prohibited transactions under Internal Revenue Code click here.

This information is for informational purposes. For information specific to your investment situation, recommends consulting with a qualified tax adviser, CPA, financial planner or investment manager. My Solo 401k Financial is a 401k provider;  therefore, it does not offer investment or tax advice, nor sell investments.

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