Can family participate in the plan itself?
A Solo 401(k) allows real participation. Each eligible owner or employee, including a working spouse, gets their own account within the plan. Contributions, balances, and investment choices are tracked separately for each participant, even though everyone shares the same plan.
Children can work in a family business and still keep the plan a Solo 401(k). A child under 21 is automatically excluded from the plan's eligibility test, no matter how many hours they work. Once a child turns 21, they either need to stay under the standard hours threshold to remain excluded, or become at least a 5 percent owner of the business, which makes them an eligible participant rather than a disqualifying employee.
An IRA works differently. It is an individual account by law, and there is no version of a "family IRA." Two spouses cannot open one shared self-directed IRA together.
It is technically possible for two spouses' separate IRAs to jointly own a single IRA LLC as partners. Self-Directed Plans does not recommend or offer this structure. The complexity and risk involved outweigh the benefit for nearly every investor, and a simpler path almost always exists. See the Knowledge Base for more on why multi-member IRA LLCs are not something we build.
Can family help run the plan?
Yes. A spouse can serve as co-manager of an IRA LLC or co-trustee of a Solo 401(k) plan trust, sharing day-to-day operational authority to help you manage your investments.
This tends to make the most sense when a family member brings something specific to the table, real relevant expertise or simply more available time than you have, rather than as a default arrangement. An adult child with real estate experience might co-manage an IRA LLC alongside a parent who values that expertise. A parent might serve as co-manager, or simply an informal advisor, for a young adult child's own IRA LLC while that child builds investing experience. Either role, formal or informal, can work well when it fits the actual situation.
What is off-limits once plan funds are involved?
Being involved in how the plan runs is different from benefiting from what the plan owns. Spouses, parents, children, and other lineal family members are Disqualified Persons. This is a narrower group than "family" in the everyday sense: siblings, cousins, aunts, uncles, and in-laws other than a lineal descendant's spouse are generally not Disqualified Persons by relationship alone. Where a Disqualified Person is involved, the plan cannot transact with them, and plan funds cannot benefit them, directly or indirectly.
A few examples make this concrete. Plan funds cannot be used to help a child buy a home, even as a loan. You cannot hire your spouse to manage a property the plan owns. Mixing plan funds with money belonging to a disqualified party, including yourself, carries significant risk and is not something to attempt without dedicated legal guidance. Being involved in decisions and management is fine. Personally benefiting from the plan's money is not.
Frequently Asked Questions
Can my spouse and I combine our IRAs into one self-directed checkbook IRA?
No. Each IRA is an individual account. Combining spousal IRA funds into a single LLC or Trust as co-owners is not something Self-Directed Plans offers, due to the complexity and risk involved. A Solo 401(k) is different, since each spouse can hold their own account within the same plan.
Does each spouse in a Solo 401(k) have their own contribution limit?
Yes. Each participant's contribution capacity is based on their own eligible compensation from the business. When both spouses earn qualifying compensation, a Solo 401(k) can effectively double what a household adds to tax-sheltered savings each year.
Can a family member get paid for serving as co-manager or co-trustee?
No. Serving in the role is permitted. Taking compensation from the plan for that service is a prohibited transaction, whether it is you or a family member in the role.
Is hiring a family member ever allowed for plan-related work?
Not if that family member is a Disqualified Person, spouses, parents, children, and their spouses are always off-limits for paid plan work regardless of terms. A sibling, cousin, or other more distant relative is not automatically disqualified, though the transaction still needs to be genuinely arm's length, at a fair market rate, for real services rendered. This is a fact-specific area worth confirming before proceeding.
Next steps
Family involvement looks different depending on which structure you are working with. See Solo 401(k) eligibility: key things to know for the owner and employee rules that govern spousal and family participation, or use the Plan Finder to see how your household's situation maps to a structure.