The short answer
What is a self directed solo 401k?
A self directed solo 401k is a one-participant business retirement plan whose documents and provider permit the intended investments. The IRS describes a one-participant plan as covering a business owner with no employees, or that owner and spouse. It is a 401(k) plan, with different eligibility and administration from an IRA.[1][2]
- 01YoudecideChoose and check the investment
- 02Custodianholds the accountAdministers the IRA and its assets
- 03Dealersells metalQuotes the product and price
- 04Depositorystores itHolds metal under the custody arrangement
Who can use a one-participant 401(k)?
Start with the business and employees, not with the desire to buy a particular asset.
The individual-account definition starts from a different structure. Ask a qualified plan professional which arrangement the business can actually maintain.
A one-participant 401(k) covers a business owner with no employees, or that owner and spouse. Hiring eligible employees changes the plan’s obligations.[1]
- 01BusinessIs there an owner-operated business?
A personal investment preference alone does not establish a one-participant business plan.
- 02EmployeesDoes the business have eligible common-law employees?
The IRS says hiring eligible employees removes the no-testing advantage and can require their inclusion.
- 03Plan documentsDoes the plan permit the intended holding?
Confirm the exact asset and administration arrangement in the documents before moving money.
How does a solo plan compare with a self-directed IRA?
The business eligibility, contribution calculation and reporting differ even if both structures can offer alternative investments.
An IRA with Roth tax treatment is still an IRA. Do not apply Roth IRA contribution-income thresholds to a business plan by analogy.
Scroll horizontally to read every column →
| Attribute | Individual retirement account | One-participant 401(k) |
|---|---|---|
| Who establishes it? | An eligible individual, subject to IRA rules | A business for an eligible owner-only arrangement |
| Contributions | IRA annual allowance and compensation/eligibility tests | Employee and employer capacities, compensation and plan limits |
| Investment access | Custodian’s permitted menu | Plan documents and provider’s permitted menu |
| Administration | IRA agreement and custodian processes | Plan documents, records and applicable plan filings |
What are the relevant 2026 contribution limits?
The IRS publishes separate employee-deferral and total defined-contribution limits; an owner’s actual amount depends on the compensation calculation and other conditions.
The owner wears both employee and employer hats, according to the IRS. The total is not simply a second personal IRA allowance. Contributions to other plans and special catch-up conditions may matter; have the calculation reviewed for the business.
The 2026 basic employee elective-deferral limit for 401(k) plans is $24,500. Compensation, other plan deferrals and catch-up rules can change what an owner may contribute.[3]
For 2026, the defined-contribution plan limit under section 415(c) is $72,000 before catch-up contributions, subject to compensation and other applicable limits. It is not an automatic contribution allowance for every business owner.[4]
Can a self-directed solo 401(k) hold physical metal?
Do not assume so from the plan’s marketing name: check the governing documents, provider acceptance and applicable investment restrictions.
The IRA metal-rule explanation helps identify the product and possession questions, but it is not a complete solo-plan manual. Get written confirmation of how the proposed plan’s metal holding, storage and recordkeeping will work.
The IRS investment FAQs say plan documents and the employer determine permitted choices within the law. Participant-directed accounts face the collectibles restriction with specific precious-metal exceptions.[2]
Your document check
- Does the executed plan document permit this exact type of holding?
- Who is legally responsible for plan administration and asset custody?
- How will ownership, valuation and storage be documented?
- What are the rules for benefit payments or a later plan termination?
When does Form 5500-EZ become a concern?
A one-participant plan generally has an annual filing obligation at the IRS asset threshold; smaller and terminating plans need their own filing checks.
The threshold is not permission to ignore records while the balance is lower. Identify who prepares the filing, which assets count and how the plan’s final year will be handled. This guide does not provide a filing service.
A one-participant plan generally files Form 5500-EZ when year-end assets reach $250,000 or more. Smaller plans may be exempt from the annual filing rule; final-year filing needs separate attention.[5]
How should you choose between the structures?
Resolve eligibility and administration first, then compare the complete costs and the investment’s role in your retirement plan.
The control and responsibility comparison is useful for either decision. The personal-benefit examples show why retirement ownership must be kept separate from personal use. If an IRA is the chosen structure, follow the IRA opening sequence rather than using business-plan paperwork.
This publication’s two-partner comparison concerns published metals-IRA arrangements. It does not rank solo 401(k) administrators or verify their plan documents.
What else do readers ask?
How much does it cost to open a Solo 401k?
This guide has no verified provider-specific solo-plan fee schedule. Request plan establishment, ongoing administration, filing, asset, storage and exit charges in writing.
Which 401(k) providers are the best?
This publication does not rank solo-plan providers. Choose an administrator whose documented scope fits the business, employee situation, asset and reporting requirements.
Is a solo 401(k) just another self-directed IRA?
No. It is a business retirement plan. The IRS gives one-participant plans their own eligibility and administration framework. [1]
Sources and checked records
Rule sources checked November 3, 2026. Annual figures keep the year stated by the source; company tables show their original field dates.
- IRS: one-participant 401(k) plansAccessed November 3, 2026.
- IRS: retirement plan investments FAQsAccessed November 3, 2026.
- IRS: 2026 employee deferral limitAccessed November 3, 2026.
- IRS Notice 2025-67: 2026 plan limitsAccessed November 3, 2026.
- IRS: one-participant plan reportingAccessed November 3, 2026.
Changes to this page
— First edition: added eligibility-first decisions, IRA comparison, 2026 IRS limit context and the general Form 5500-EZ threshold.