Does Each Solo 401(k) Plan File a Separate 5500-EZ? (w/Examples) + FAQs

This article reflects federal IRS rules as of June 2026 and covers the 2025 plan year (the 2026 filing season). Form 5500-EZ is a federal filing with no separate state version. Tax law changes — confirm current figures on IRS.gov before you file.

Quick Answer

Yes. Each separate one-participant 401(k) plan files its own Form 5500-EZ. But the $250,000 filing threshold is combined across all your one-participant plans. So you can owe a return on a single plan even when that one plan holds less than $250,000 by itself for the 2025 plan year.

That single rule trips up more solo savers than any other part of this form. The number on your account statement is not what decides whether you file — the total of every one-participant plan you sponsor is. Miss it, and the IRS penalty runs $250 per day, up to $150,000 per unfiled return, plus interest.

Roughly 1 million Form 5500-series returns are filed each year, and the IRS warns that small-business sponsors who skip the EZ face penalties up to $15,000 per return before any relief. The deadline is real, the math is simple once you see it, and the fix for a missed year is cheaper than most people fear.

Here is what you will walk away knowing:

🧾 Whether your situation needs one Form 5500-EZ or several
➕ How to add up multiple plans to test the $250,000 threshold the right way
👥 What happens when a spouse, a partner, or a second business is involved
⏰ The exact deadline, the extension trick, and what a late filing costs
🛟 How to fix missed years for $500 instead of thousands

What Form 5500-EZ Actually Is

Form 5500-EZ is the annual information return for a one-participant retirement plan. A one-participant plan covers only a business owner (or the owner and spouse), or only business partners (and their spouses). It does not cover any common-law employees. A solo 401(k) is the most familiar example, but a solo defined benefit plan or a solo cash balance plan can also be a one-participant plan.

The form reports basic facts to the IRS: the plan’s name, the sponsor, the plan number, total assets, contributions, and distributions. It does not calculate any tax. It is purely an information filing required under Internal Revenue Code Section 6058(a). The consequence of treating it as optional is steep, because the IRS can assess a daily penalty even though no tax is due.

A common misconception is that the EZ is the same as the regular Form 5500. It is not. A one-participant plan cannot use Form 5500 or Form 5500-SF — those are for plans with non-owner employees and carry public disclosure and audit exposure the EZ avoids. What you should do: confirm your plan truly covers only owners and spouses (or partners and spouses), because the moment you hire a non-spouse, non-partner employee who becomes eligible, you leave EZ territory.

Who counts as a “one-participant plan”

The IRS definition is precise. The plan must cover only an individual (or that individual and spouse) who owns the whole business, or only one or more partners and their spouses, and it must not provide benefits to anyone else. A 2% shareholder of an S corporation is treated as a partner for this purpose.

The consequence of getting this wrong is using the wrong form entirely. If a plan that should have filed the full Form 5500 files an EZ instead, the filing can be treated as deficient. What you should do: review your plan census every year before filing, and if you have added any eligible W-2 employee who is not a spouse, talk to a third-party administrator about switching forms.

The Core Rule: One Plan, One Return — But Aggregate the Assets

Each distinct plan is a separate legal arrangement, so each one files its own Form 5500-EZ with its own plan number. If you sponsor two genuinely separate plans, you may end up filing two returns. That is the “separate return per plan” half of the answer.

The half that surprises people is the threshold test. A one-participant plan does not have to file for 2025 if the total of that plan’s assets plus the assets of all other one-participant plans the same employer maintains did not exceed $250,000 at the end of the 2025 plan year — unless 2025 is the plan’s final year. The threshold is combined; the return is per plan.

So the two halves work together like this. First, add up every one-participant plan you maintain to see if you cross $250,000. If you do, then file a separate Form 5500-EZ for each plan that has assets — even a plan that, on its own, holds far less than $250,000. The aggregation decides whether you file at all; it does not let you combine several plans onto one form.

Why the assets get aggregated

The aggregation rule exists so a sponsor cannot dodge reporting by splitting savings across several small plans. The IRS looks at the sponsor, not the account. Per My Solo 401k Financial, the $250,000 limit “is not per account” — all plan assets, all participants, and all sources (Roth and pretax) are added together.

The consequence of misreading this is a missed filing you never knew you owed. A reader who sees $180,000 in one plan and $120,000 in another may assume both are under the line, when together they are $300,000 — over the threshold. What you should do: total every one-participant plan as of December 31, 2025, before you decide you are exempt.

Which Situation Applies to You?

Your answer depends entirely on how your plans and people are arranged. Find the row that matches you, then read the section it points to.

You have one solo 401(k), total under $250,000. No filing for 2025. Skip to deadlines and keep watching the balance.
You have one solo 401(k), total $250,000 or more. File one Form 5500-EZ. Read the worked example below.
You and your spouse share one solo 401(k). Still one plan, one return; combine both of your balances for the test.
You sponsor two separate solo 401(k) plans. Aggregate both for the threshold; if you cross it, file two returns. Read the multi-plan example.
You have a solo 401(k) and a solo defined benefit plan. Both are one-participant plans; aggregate them and file a separate EZ for each.
You own two businesses, each with its own plan. Controlled-group rules may force aggregation — this is where a professional earns their fee.

Worked Example: A Single Plan Over the Line

Numbers make this concrete. Here is the simplest case, fully worked.

Maria runs a one-person design studio and sponsors one solo 401(k). On December 31, 2025, her account holds $264,500 — $210,000 pretax and $54,500 Roth. She adds the sources together because the rule aggregates them: $210,000 + $54,500 = $264,500. That is over $250,000, so Maria must file.

Maria files one Form 5500-EZ for the 2025 plan year. Her deadline is July 31, 2026. She reports total assets of $264,500, her 2025 contributions, and any distributions. No tax is due — it is informational. What she should do next: file electronically through EFAST2 or use the IRS online form, and keep a copy with her plan records.

Worked Example: Two Plans, Two Returns

Now the case that catches people. David is a freelance engineer with two separate one-participant plans: a solo 401(k) from his current LLC holding $190,000, and an old solo 401(k) from a prior sole proprietorship holding $95,000, both as of December 31, 2025.

David tests the threshold by aggregating: $190,000 + $95,000 = $285,000. That clears $250,000, so the exemption is gone for both plans. Because each plan is a separate arrangement, David files two separate Forms 5500-EZ — one reporting $190,000, one reporting $95,000 — even though the second plan, alone, is nowhere near $250,000.

The lesson is direct: the $95,000 plan would never file on its own, but the moment the combined total crosses the line, every plan with assets reports. What David should do: file both returns by July 31, 2026, each with its own plan number, and never merge them onto one form.

Worked Example: Owner and Spouse in One Plan

Priya and her husband both work in her S corporation and both participate in the same solo 401(k). At year-end 2025, her balance is $170,000 and his is $115,000.

Because they are in one plan, this is one plan and one return. Priya still aggregates their balances for the threshold test: $170,000 + $115,000 = $285,000, which is over $250,000. She files a single Form 5500-EZ reporting $285,000 in total plan assets. She does not file two returns just because two people participate. What she should do: report the plan’s combined assets on one EZ and list the plan as covering the owner and spouse.

Scenario Tables

Each table below shows a common setup and what it means for your filing.

One plan, balance near the threshold

Your Setup at Year-End 2025	What You File
Single solo 401(k) holding $240,000	Nothing for 2025; under the combined $250,000 line
Single solo 401(k) holding $250,000 exactly	Nothing yet — the rule says assets must exceed $250,000
Single solo 401(k) holding $250,001	One Form 5500-EZ for 2025

Two separate one-participant plans

Your Setup at Year-End 2025	What You File
Plan A $120,000 + Plan B $110,000 = $230,000	Nothing; combined total stays under $250,000
Plan A $200,000 + Plan B $90,000 = $290,000	Two returns — one Form 5500-EZ for each plan
Plan A $260,000 + Plan B $5,000 = $265,000	Two returns; even the tiny plan files

Special timing situations

Your Setup	What You File
Plan terminated in 2025 with $40,000 left	A final Form 5500-EZ, regardless of the $250,000 line
First year ever, plan funded to $300,000	One Form 5500-EZ; the threshold can be crossed in year one
Plan dropped from $300,000 to $230,000 in 2025	No filing for 2025 if no other plan pushes the total over $250,000

Named Example: The Forgotten Old Plan

Tom, a consultant, opened a solo 401(k) in 2018 and rolled an old account into a second solo 401(k) he forgot to close. By the end of 2025, the active plan held $220,000 and the dormant one held $45,000. Tom assumed he was exempt because neither plan touched $250,000.

He was wrong. Aggregated, the two plans total $265,000, so both owed a Form 5500-EZ for 2025. Tom missed the July 31, 2026 deadline on both. What saved him was the IRS late-filer relief program, which let him file both delinquent returns for $500 each instead of facing penalties that could have run into five figures per return.

The Deadline, the Extension, and the Cost of Missing It

For a calendar-year plan, Form 5500-EZ is due the last day of the seventh month after the plan year ends — July 31, 2026 for the 2025 plan year. If July 31 lands on a weekend or holiday, the deadline rolls to the next business day.

You can get a one-time extension of up to 2½ months — to October 15 — by filing Form 5558 on or before the regular due date. A separate Form 5558 should be filed for each plan you want to extend, and a copy must be kept with the plan’s records. The extension is automatic and needs no IRS approval, but it cannot be filed after the original due date.

There is also a built-in extension with no form needed. A one-participant plan automatically gets more time if the plan year and the employer’s tax year match, the employer has an extension to file its federal income tax return past the normal EZ due date, and a copy of that income tax extension is kept with the plan records. You cannot stack a Form 5558 on top of this automatic extension.

Missing the deadline is expensive. The IRS penalty is $250 per day, up to $150,000 per late return, plus interest, under Code Section 6652(e) as amended by the SECURE Act. What you should do if you are about to be late: file the extension now, and if a past year was missed, use the relief program below before the IRS contacts you.

Filing electronically vs. on paper

You can file the EZ three ways: on paper with the IRS, using the IRS online Form 5500-EZ, or electronically through the DOL’s EFAST2 system. Most solo sponsors find electronic filing fastest and easiest.

Electronic filing is mandatory for some. For a plan year beginning on or after January 1, 2025, you must file electronically if you are required to file at least 10 returns of any type with the IRS during the calendar year that includes the first day of the plan year. The consequence is serious: a filer who had to file electronically but mailed paper is treated as having not filed at all. What you should do: if your overall return count is near 10, file the EZ electronically to be safe.

The Late-Filer Relief Program (Your Cheap Fix)

If you missed one or more years, do not panic. Under Revenue Procedure 2015-32, the IRS runs a permanent penalty-relief program for late EZ filers. You file the delinquent returns and pay a flat fee instead of the daily penalty.

The fee is $500 per delinquent return, capped at $1,500 per plan for three or more late returns of the same plan. Compared with $250 per day, this is a fraction of the exposure. The catch matters: you are not eligible if the IRS has already assessed you a late penalty for that filing. Once a notice arrives, this door closes.

What you should do: gather every missed year, file them together under the program, and make the check payable to the “United States Treasury.” If you have already been assessed a penalty, your remaining route is a reasonable-cause request, which is harder and not guaranteed.

Mistakes to Avoid

Each error below has a real cost attached.

Testing the threshold per account instead of combined. You skip a required filing and face $250-per-day penalties on a return you never knew you owed.
Merging two plans onto one Form 5500-EZ. Each plan needs its own return and plan number; combining them creates a deficient filing.
Forgetting a dormant or rolled-over plan. That ignored balance can push your total over $250,000 and trigger filings for all your plans.
Assuming exactly $250,000 requires a filing. The rule says assets must exceed $250,000, so a plan at precisely $250,000 does not file.
Skipping the final-year return. A terminating plan must file a final EZ even if it is far under $250,000; missing it leaves the plan open in IRS records.
Mailing paper when e-filing is mandatory. If you owed 10+ returns, a paper EZ counts as never filed, and penalties keep running.
Filing Form 5558 after the due date. The extension only works if filed on or before July 31; a late 5558 does nothing.
Waiting until the IRS sends a notice. Once a penalty is assessed, you lose access to the $500 relief program.

Do’s and Don’ts

Do total every one-participant plan as of December 31 before deciding you are exempt — because the threshold is combined, not per plan.
Do file a separate Form 5500-EZ for each plan once you cross the line, so each plan is reported under its own number.
Do keep copies of every filed EZ and any extension with your plan records, since the IRS can ask years later.
Do use the $500 relief program for any missed year before the IRS contacts you, because it is far cheaper than the daily penalty.
Do file electronically through EFAST2 if you are near the 10-return mandatory e-file count, to avoid a “not filed” result.
Don’t treat the EZ as optional just because no tax is due, since the penalty applies to the filing, not to any tax.
Don’t combine a spouse’s and an owner’s separate plans onto one form; only a shared single plan uses one return.
Don’t assume two businesses mean two unrelated plans — controlled-group rules can force aggregation.
Don’t rely on memory for old accounts; pull statements for every plan you have ever opened.
Don’t stack a Form 5558 on top of the automatic income-tax extension, because it is not allowed.

Pros and Cons of the One-Participant Filing Setup

Pro: The EZ is short and informational, so a simple solo plan is quick to report — usually a single page of data.
Pro: One-participant plans skip the public disclosure and audit rules that burden full Form 5500 filers.
Pro: The automatic income-tax-linked extension can give you extra time with no separate form.
Pro: The $500 relief program offers a cheap, predictable fix for missed years before assessment.
Pro: Filing each plan separately keeps your records clean if you later close one plan.
Con: The combined-asset threshold is easy to misread and triggers surprise filings.
Con: Multiple plans mean multiple returns, each with its own deadline and its own penalty exposure.
Con: A single missed return can accrue $250 per day, up to $150,000, plus interest.
Con: Mandatory e-filing rules can catch sponsors who file many other returns.
Con: Relief disappears the moment the IRS assesses a penalty, so timing is unforgiving.

What to Do Next

Take these steps in order before the deadline.

Pull year-end statements for every one-participant plan you sponsor, dated December 31, 2025.
Add them all together — every plan, every participant, pretax and Roth — and compare the total to $250,000.
If you are over, prepare a separate Form 5500-EZ for each plan, using each plan’s own number.
File by July 31, 2026, or file Form 5558 on or before that date to reach October 15, 2026.
Choose your method — EFAST2, the IRS online form, or paper — and e-file if you owe 10+ returns overall.
If you missed a past year, file under the Rev. Proc. 2015-32 relief program now, before any IRS notice.
Call a professional if you own multiple businesses, have a defined benefit plan, or have employees — controlled-group and coverage rules get complex fast.

This article is educational and is not a substitute for advice from a licensed CPA or tax attorney for your specific situation. A solo plan with one owner is usually a do-it-yourself filing. The moment you add a second business, a non-spouse employee, or a defined benefit plan, the cost of professional help is small next to the penalty for getting it wrong.

FAQs

Does each solo 401(k) plan file its own Form 5500-EZ? Yes. Each separate one-participant plan files its own return with its own plan number. You never combine multiple plans onto a single Form 5500-EZ, even though you combine their assets to test the $250,000 threshold.

Is the $250,000 limit per account or combined? Combined. You add up all one-participant plans you maintain, all participants, and all sources (Roth and pretax). If the total exceeds $250,000 at year-end 2025, the exemption is gone for every plan with assets.

Do my spouse and I file two returns if we share one plan? No. One shared plan is one plan and one return. You combine both balances for the threshold test, but you report the plan’s total assets on a single Form 5500-EZ.

What is the deadline for the 2025 plan year? July 31, 2026 for a calendar-year plan — the last day of the seventh month after the plan year ends. An extension to October 15, 2026 is available by filing Form 5558 on time.

How much is the penalty for not filing? $250 per day, up to $150,000 per unfiled return, plus interest, under Code Section 6652(e). The penalty applies to the missing filing even though Form 5500-EZ reports no tax due.

Can I fix a year I missed? Yes. Under Revenue Procedure 2015-32, you file the late return and pay $500 per delinquent return, capped at $1,500 per plan. You lose eligibility once the IRS assesses a penalty for that year.

Do I file if my plan holds exactly $250,000? No. The rule requires assets to exceed $250,000. A plan sitting at precisely $250,000, with no other plan pushing the combined total higher, is not yet required to file for 2025.

Does a terminating plan have to file? Yes. A plan’s final year requires a final Form 5500-EZ regardless of the $250,000 threshold. Check the “final return” box so the IRS closes the plan in its records.

Can I file Form 5500-EZ on paper? Yes, unless e-filing is mandatory for you. For plan years beginning on or after January 1, 2025, you must e-file through EFAST2 if you must file 10 or more IRS returns of any type that year.

Is there a state version of Form 5500-EZ? No. Form 5500-EZ is a federal IRS filing with no separate state equivalent. States do not require their own version, though unrelated state business filings may still apply to your company.

Does a solo defined benefit plan also count toward the threshold? Yes. A solo defined benefit or cash balance plan is also a one-participant plan, so its assets aggregate with your solo 401(k) for the $250,000 test, and it files its own EZ.

What if I own two businesses with separate plans? It depends. Controlled-group rules can force you to aggregate the plans and may even affect whether the plans qualify as one-participant plans. This is a situation where a retirement-plan professional is worth the cost.

Word count: approximately 2,950. Note to editor: the source instructions target 3,400+ words; this topic is genuinely narrow, and the sections above contain only non-repetitive, useful material. Further expansion would require padding, which the instructions forbid — flagging rather than padding.

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