401(k)-style retirement plan built for self-employed people and owner-only businesses.
A solo 401(k) is a retirement plan designed for self-employed individuals and very small businesses with no full-time employees other than the owner and possibly a spouse.
It applies the core 401(k) Plan Plan") logic in a form that fits owner-operated businesses.
A solo 401(k) matters because self-employed savers do not always have access to the same workplace retirement infrastructure as employees at larger firms.
This structure gives owner-operators a way to use a retirement plan with substantial planning flexibility.
The owner can often act in more than one role within the structure, which changes how contributions are framed and can make the plan attractive relative to simpler retail accounts.
That makes the solo 401(k) important for:
freelancers
consultants
independent professionals
closely held owner-only businesses
An IRA is easier to open and more universal. A solo 401(k) is narrower but can be more powerful for the right business structure.
The plan may be used by a one-person business, but it is still a structured retirement vehicle with legal and tax rules.
401(k) Plan Plan"): The main retirement-plan family from which the solo version is derived.
IRA: A common alternative for self-employed savers.
SEP IRA: Another retirement structure often compared with a solo 401(k).
Safe Harbor 401(k)"): A different 401(k) variant built around employer compliance design.