Potentially yes. If you own or control more than one business, the IRS may treat those businesses as a single employer for retirement plan purposes. When that happens, employees across all businesses in the group are counted together, and if any business in the group has qualifying employees, a Solo 401(k) may not be available to any of them.
A Solo 401(k) is available to owner-only businesses. The rules exist to prevent business owners from giving themselves retirement plan benefits that aren't offered to their employees. Controlled group and related service group rules extend this principle across multiple businesses under common ownership, so you can't sidestep the employee requirement simply by keeping businesses in separate entities.
The core test is ownership and control. If the same owner or group of owners holds significant ownership or effective control across multiple businesses, those businesses may be treated as one for benefits purposes. Specific ownership thresholds apply: 80% ownership and 50% effective control are the key benchmarks, but the rules involve several overlapping tests and can be difficult to apply without professional guidance.
If your owner-only business stands alone, meaning you and your spouse do not have significant ownership interests in other businesses with qualifying employees, controlled group rules are unlikely to affect your eligibility. The vast majority of solo entrepreneurs fall into this category.
The analysis becomes more complex if you have ownership stakes in multiple businesses, if your spouse owns or manages a separate business with employees, or if your businesses share services, management, or significant revenue relationships with each other. Any of these circumstances can trigger controlled group or affiliated service group analysis.
This is not an area where general guidance is sufficient. The rules are technical, the fact-specific analysis matters, and the consequences of operating an ineligible plan are significant. If your business situation involves multiple entities or shared ownership, consult a qualified tax or ERISA attorney before establishing a Solo 401(k).
My spouse has a business with employees. Does that disqualify me?
It depends on the degree of connection between the businesses. In many cases, spousal ownership is combined for controlled group purposes, meaning your spouse's employees could affect your eligibility. However, exceptions exist when the businesses are genuinely separate and neither spouse holds ownership or a directing role in the other's company. This is exactly the kind of scenario that warrants a professional review before proceeding.
I have two businesses and neither has employees. Am I fine?
If both businesses are owner-only and have no qualifying employees, you are likely eligible, and in fact, both businesses can co-sponsor a single Solo 401(k), allowing you to combine income from both for contribution purposes. The second business joins the plan as a participating employer, which allows its income to be used for plan contributions alongside the primary sponsoring business.
This information is provided for educational purposes only and should not be interpreted as tax, legal, or investment advice. Readers are encouraged to consult a qualified professional who can offer guidance based on their personal situation.