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Form 5500-EZ: The Annual Return for Solo 401(k) and One-Participant Plans

Form 5500-EZ is the annual return for one-participant retirement plans, such as a solo 401(k) that covers only a business owner, or the owner and their spouse, and certain foreign plans. You only have to file it once the plan's assets, together with any other one-participant plans the business maintains, are more than $250,000 at the end of the plan year, or in the plan's final year.

Everything below comes from the IRS Instructions for Form 5500-EZ (2025), the form and the IRS About Form 5500-EZ page, as of October 2026.

What counts as a one-participant plan

The instructions define it as a retirement plan, either a defined benefit pension plan or a defined contribution plan such as a profit-sharing plan, other than an ESOP, that:

  • Covers only you, or you and your spouse, and you or you and your spouse own the entire business, incorporated or not; or
  • Covers only one or more partners, or partners and their spouses, in a business partnership, with a 2% shareholder of an S corporation treated as a partner; and
  • Doesn't provide benefits for anyone else.

If you hire an employee who joins the plan, it stops being a one-participant plan and the regular Form 5500 rules come into play. A one-participant plan can't file on Form 5500 or 5500-SF, whatever it filed before.

The $250,000 test

Situation at the end of the 2025 plan yearForm 5500-EZ for 2025?
Total assets of all your one-participant plans $250,000 or lessNot required, unless 2025 is the final plan year
Total assets of all your one-participant plans more than $250,000Required for each plan, including those under $250,000
Final plan year, with all assets distributedRequired, with the final return box checked

That middle row is the trap. The test adds your plans together, so a small second plan that's under the line on its own still needs a return once the combined total passes $250,000. These figures are as of October 2026.

When it's due

File by the last day of the 7th calendar month after the end of the plan year. For a calendar-year plan, that's July 31. For a short plan year, it's the last day of the 7th month after the short year ends, with the dates shown at the top of the form. Form 5558 gets a one-time extension of up to two and a half months; don't attach the 5558 to the return, but check its box in Part I, line B.

Who doesn't file

Below the asset line, a one-participant plan doesn't have to file for the year, unless it's the final plan year. The instructions' own example makes the combined test clear: if a plan meets every requirement for the 5500-EZ and its assets, alone or together with the employer's other one-participant plans, are more than $250,000 at the end of the 2025 plan year, a return is due for each of those plans, including any with less than $250,000 on its own. So don't judge each account separately. Add up every one-participant plan the business keeps, check the total at the plan year end, and decide from that number.

Amending a return

If the plan previously filed electronically on Form 5500-SF or 5500-EZ, an amended return also goes in electronically, on the prior-year 5500-EZ for an earlier year or the current-year form for the current year. Check box A(2), an amended return, in Part I.

Paper or EFAST2

  1. You can file on paper with the IRS in Ogden, Utah, or electronically through the Department of Labor's EFAST2 system, online or through an approved vendor.
  2. If you're required to file at least 10 returns of any type with the IRS in the calendar year, you must file the 5500-EZ electronically for plan years beginning on or after January 1, 2024.
  3. Late returns under the penalty relief program must go on paper with box D checked; they can't be filed through EFAST2.

The penalty and the relief program

The instructions quote Code section 6652(e): a penalty of $250 a day, up to a maximum of $150,000 per plan year, for not filing by the due date. That's real exposure for a return many solo owners don't know exists.

The IRS Late Filer Penalty Relief Program offers administrative relief from those penalties for non-Title I plans, which includes one-participant plans, when the delinquent returns are filed under the program's rules, with Form 14704 attached to the front of the oldest delinquent return. If you've missed years, read that section of the instructions before filing anything.

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Filling in the 5500-EZ

  • Part I: the plan year and the type of return, such as first, amended, final or short plan year, and whether you used a Form 5558 extension.
  • Part II: basic plan information: plan name and number, the employer, its EIN and address, and the plan administrator.
  • Part III: financial information about the plan's assets and liabilities for the year.
  • Part IV: plan characteristics.
  • Part V: compliance and funding questions.

If your business address changes, the instructions point to Form 8822-B to tell the IRS. For help, the IRS Help Desk for this form is 877-829-5500 and the EFAST2 Help Desk is 1-866-463-3278.

The verdict

If you run a solo 401(k), set a reminder every January to add up the year-end balances of all your one-participant plans. Under $250,000 combined, there's nothing to file. Over it, file a 5500-EZ for every plan by July 31 for a calendar-year plan, and don't forget the final-year return when you close the plan. The plan's contributions themselves flow from your business return, such as Schedule C for a sole proprietor.

Frequently asked questions

Who has to file Form 5500-EZ?

One-participant plans and certain foreign plans, once the combined assets of all the employer's one-participant plans are more than $250,000 at the end of the plan year, and every plan in its final plan year.

When is Form 5500-EZ due?

By the last day of the 7th calendar month after the end of the plan year, which is July 31 for a calendar-year plan.

What is the penalty for not filing Form 5500-EZ?

Code section 6652(e) imposes $250 a day, up to a maximum of $150,000 per plan year.

Can I file Form 5500-EZ electronically?

Yes, through EFAST2. Filers required to file at least 10 returns of any type with the IRS in the calendar year must file it electronically.

Can a solo 401(k) file Form 5500 instead of 5500-EZ?

No. A one-participant plan or foreign plan can't file on Form 5500 or Form 5500-SF.

Published and maintained by the Lilach Bullock team, covering marketing, AI and business growth.
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