Learn - Can I Have a Solo 401(k) If I Own Multiple Businesses?

If you’re self-employed and run more than one business, it’s natural to wonder — can I open a Solo 401(k) for each business? The short answer: it depends on ownership structure and control group rules.

Watch: Find out if you can have multiple 401k plans if you own multiple businesses

Let’s break it down.

One Owner, Multiple Businesses = One Solo 401(k)

If you own 100% of two or more businesses, the IRS views those businesses as a single employer under the common control regulations.

That means you can only open one Solo 401(k) plan — not one per business.

Example:

You own two LLCs with no full-time W-2 employees (other than yourself or your spouse).

The IRS treats these businesses as one employer.
You open one Solo 401(k) plan that covers both LLCs.
Your contributions are based on your total combined self-employment income from both businesses.
You’ll file one Form 5500-EZ when required (if your plan balance exceeds $250,000 or the plan terminates).

You cannot double up on Solo 401(k) contributions or loans. The IRS limits apply to you as an individual, not per business.

Two Owners, Separate Businesses = Separate Solo 401(k)s Possible

You can have more than one Solo 401(k) if your businesses are not under common control.

Example:

You own 100% of Business A (no full-time employees).
You also co-own Business B, owning 50% or less, and your business partner is not related to you.
Business B also has no full-time W-2 employees.

✅ You may open a separate Solo 401(k) for each business.
🚫 But you cannot do this if you own 80% or more of both entities — that triggers the common control rule.

Beware of the 80% Ownership Test

Many business owners try to form multiple entities to “separate” employees or increase contribution limits. Unfortunately, this strategy fails under IRS control group rules.

Example:

You own 80% or more of XYZ Marketing LLC, which employs full-time staff.
You also own 100% of ABC Consulting LLC, which has no employees.

Even though ABC has no staff, the IRS views both as one employer because of your 80% ownership overlap.
Result: No Solo 401(k) eligibility because the “group” (you + both companies) employs full-time W-2 workers.

Contribution Rules When You Have Multiple Plans

If you’re eligible to have two separate Solo 401(k) plans:

Employee deferrals ($23,500 in 2025; $31,000 if age 50+) are aggregated across all plans.
Employer (profit-sharing), and voluntary after-tax contributions are calculated separately for each business based on its own net income.

This means you can maximize employer contributions and voluntary after-tax contributions for each entity, but your employee deferrals apply to your total across both.

Compliance & Reporting

You must follow IRS aggregation rules for contribution limits and Form 5500-EZ filings.
Contributions must be made from the business bank account that sponsors the plan.
Keep clean records showing which business made which contributions.
File Form 5500-EZ annually once your plan balance exceeds $250,000 — or when terminating the plan, even if it’s below that threshold.

Common Mistakes to Avoid

Trying to double employee deferrals.
Ignoring control group or affiliated service group rules.
Splitting entities to “get around” employee eligibility rules.
Forgetting to file Form 5500-EZ when required.

Key Takeaways

Scenario	Result
You own 100% of two LLCs	One Solo 401(k) plan
You own <80% of a second business with an unrelated partner	Separate Solo 401(k) plans allowed
Any business you own employs full-time W-2 workers	No Solo 401(k) eligibility
Control group applies (≥80% ownership overlap)	One plan only