A Self-Directed Solo 401(k) is one of the most powerful retirement tools available to self-employed individuals. However, when your business activity ends—or you are no longer eligible to sponsor the plan—the Solo 401(k) must be formally closed.
Closing a Solo 401(k) is not automatic. Failing to close a Solo 401(k) properly can result in significant IRS penalties, often reaching tens of thousands of dollars.
This guide explains when a Solo 401(k) must be closed, how to close it correctly, and what happens to the assets inside the plan.
Watch: Complete breakdown of how to formally close a solo 401k with the IRS
When Are You Required to Close a Solo 401(k)?
Unlike a traditional employer 401(k), a Solo 401(k) is sponsored by your self-employed business. If that business ends, the plan cannot continue.
You are required to close your Solo 401(k) if:
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Your self-employed business shuts down
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You are no longer performing material self-employment services
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You transition to full-time employment and no longer have self-employment income
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You fully retire
This is different from a corporate employer 401(k), which continues to exist even after you leave the job. With a Solo 401(k), you are both the employer and the plan sponsor, so the plan must be terminated when the business ends.
Why Proper Solo 401(k) Plan Termination Matters
A Solo 401(k) does not automatically close when your business stops operating.
If the plan is not formally terminated:
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The IRS continues to treat it as an active retirement plan
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Annual reporting obligations remain in force
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Failure to file required forms can trigger large IRS penalties
One of the most common (and costly) mistakes is failing to file the final Form 5500-EZ, which can result in penalties ranging from $10,000 to well over $200,000.
Required IRS Forms to Close a Solo 401(k)
When closing a Solo 401(k), two IRS filings are required, regardless of the account balance.
1. Form 1099-R (Required)
Form 1099-R reports what happens to the assets when the plan is closed:
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Direct rollover to an IRA or employer 401(k) → reported as non-taxable
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Taxable distribution paid to you personally → reported as taxable income
This form is typically issued by January/February of the year following plan termination.
2. Final Form 5500-EZ (Always Required)
A final Form 5500-EZ must be filed, even if:
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The account balance is under $250,000
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The plan never previously required annual 5500-EZ filings
The $250,000 threshold applies only to ongoing plans.
All Solo 401(k) plans must file a final Form 5500-EZ when closed, regardless of value
What Happens to the Assets Inside the Solo 401(k)?
When closing the plan, you have several options for handling the assets.
Option 1: Roll the Assets to an IRA (Most Common)
You may complete a non-taxable direct rollover to:
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Traditional IRA
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Roth IRA (for Roth Solo 401(k) assets)
Important:
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Stocks, ETFs, and mutual funds do not need to be liquidated
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Assets can be transferred in-kind, preserving market exposure
This is commonly done when both the Solo 401(k) and IRA are held at the same brokerage, allowing for seamless in-kind transfers.
Option 2: Roll the Assets to a New Employer’s 401(k)
If you return to full-time employment and your new employer’s plan accepts rollovers:
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Assets can be rolled into that employer plan
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Some plans require liquidation if they do not accept certain securities
Option 3: Take a Taxable Distribution (Least Favorable)
If you choose to distribute the funds personally:
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The entire balance is taxed as ordinary income
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A 10% early withdrawal penalty may apply if under age 59½
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State taxes may also apply
This option is generally used only when no rollover alternative is desired.
What If the Solo 401(k) Holds Alternative Investments?
If your Solo 401(k) owns assets such as:
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Real estate
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Cryptocurrency
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Private equity
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Promissory notes
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Precious metals
You are not required to liquidate them.
Instead, you may:
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Open a Self-Directed IRA
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Transfer the assets in-kind
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Maintain continued tax-deferred or tax-free status
For real estate, this involves retitling the property into the name of the IRA custodian for the benefit of your IRA.
Outstanding Solo 401(k) Participant Loans
If you have an outstanding Solo 401(k) loan at the time of closure:
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The loan must be repaid in full before plan termination
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If not repaid, the balance is treated as a taxable distribution
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Taxes and penalties may apply
This step is frequently overlooked and can create unexpected tax liability if not handled properly.
Final Thoughts: Don’t Leave Plan Closure to Chance
Closing a Self-Directed Solo 401(k) is not optional when self-employment ends—and it must be done correctly.
A proper closure includes:
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Filing Form 1099-R
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Filing a final Form 5500-EZ
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Correctly rolling over or distributing assets
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Addressing any outstanding participant loans
When handled properly, closing a Solo 401(k) is straightforward. When ignored or done incorrectly, it can become expensive, stressful, and time-consuming.
Planning ahead—especially before year-end—can help you avoid penalties and preserve your retirement savings.
